Technetium- and rhenium-bis (heteroaryl) complexes, and methods of use thereof

ABSTRACT

One aspect of the invention relates to complexes of a radionuclide with various heteroaryl ligands, e.g., imidazolyl and pyridyl ligands, and their use in radiopharmaceuticals for a variety of clinical diagnostic and therapeutic applications. Another aspect of the invention relates to imidazolyl and pyridyl ligands that form a portion of the aforementioned complexes. Methods for the preparation of the radionuclide complexes are also described. Another aspect of the invention relates to imidazolyl and pyridyl ligands based on derivatized lysine, alanine and bis-amino acids for conjugation to small peptides by solid phase synthetic methods. Additionally, the invention relates to methods for imaging regions of a mammal using the complexes of the invention.

RELATED APPLICATIONS

This application is a U.S. national phase entry application ofPCT/US2005/004407, filed Feb. 14, 2005, which in turn claims the benefitof U.S. Provisional Patent Application Ser. No. 60/543,986, filed Feb.12, 2004; and U.S. Provisional Patent Application Ser. No. 60/566,635,filed Apr. 29, 2004. The contents of all are hereby incorporated byreference.

BACKGROUND OF THE INVENTION

Radiopharmaceuticals may be used as diagnostic or therapeutic agents byvirtue of the physical properties of their constituent radionuclides.Thus, their utility is not based on any pharmacologic action per se.Most clinically-used drugs of this class are diagnostic agentsincorporating a gamma-emitting nuclide which, because of physical,metabolic or biochemical properties of its coordinated ligands,localizes in a specific organ after intravenous injection. The resultantimages can reflect organ structure or function. These images areobtained by means of a gamma camera that detects the distribution ofionizing radiation emitted by the radioactive molecules.

In radioimaging, the radiolabel is a gamma-radiation emittingradionuclide and the radiotracer is located using a gamma-radiationdetecting camera (this process is often referred to as gammascintigraphy). The imaged site is detectable because the radiotracer ischosen either to localize at a pathological site (termed positivecontrast); alternatively, the radiotracer is chosen specifically not tolocalize at such pathological sites (termed negative contrast).

Many of the procedures presently conducted in the field of nuclearmedicine involve radiopharmaceuticals which provide diagnostic images ofblood flow (perfusion) in the major organs and in tumors. The regionaluptake of these radiopharmaceuticals within the organ of interest isproportional to flow; high flow regions will display the highestconcentration of radiopharmaceutical, while regions of little or no flowhave relatively low concentrations. Diagnostic images showing theseregional differences are useful in identifying areas of poor perfusion,but do not provide metabolic information of the state of the tissuewithin the region of apparently low perfusion.

It is well known that tumors often have regions within their mass whichare hypoxic. These result when the rapid growth of the tumor is notmatched by the extension of tumor vasculature. A radiopharmaceuticalwhich localizes preferentially within regions of hypoxia could be usedto provide images which are useful in the diagnosis and management oftherapy of tumors, as suggested by Champman, “Measurement of TumorHypoxia by Invasive and Non-Invasive Procedures—A Review of RecentClinical Studies”, Radiother. Oncol., 20(S1), 13-19 (1991).Additionally, a compound which localizes within the hypoxic region oftumors, but is labeled with a radionuclide with suitable alpha- orbeta-emissions could be used for the internal radiotherapy of tumors. Inthe brain or heart, hypoxia typically follows ischemic episodes producedby, for example, arterial occlusions or by a combination of increaseddemand and insufficient flow.

However, many radionuclides are less than ideal for routine clinicaluse. For example, the positron-emitting isotopes (such as ¹⁸F) arecyclotron-produced and short-lived, thus requiring that isotopeproduction, radiochemical synthesis, and diagnostic imaging be performedat a single site or region. The costs of procedures based onpositron-emitting isotopes are very high, and there are very few ofthese centers worldwide. While ¹²³I-radiopharmaceuticals may be usedwith widely-available gamma camera imaging systems, ¹²³I has a 13-hourhalf-life (which restricts the distribution of radiopharmaceuticalsbased on this isotope) and is expensive to produce. Nitroimidazoleslabeled with ³H are not suitable for in vivo clinical imaging and can beused for basic research studies only.

A number of factors must be considered for optimal radioimaging inhumans. To maximize the efficiency of detection, a radionuclide thatemits gamma energy in the 100 to 200 keV range is preferred. To minimizethe absorbed radiation dose to the patient, the physical half-life ofthe radionuclide should be as short as the imaging procedure will allow.To allow for examinations to be performed on any day and at any time ofthe day, it is advantageous to have a source of the radionuclide alwaysavailable at the clinical site.

A variety of radionuclides are known to be useful for radioimaging,including Ga-67, Tc-99m, In-111, I-123, and I-131. The preferredradioisotope for medical imaging is Tc-99m. Its 140 keV gamma-photon isideal for use with widely-available gamma cameras. It has a short (6hour) half life, which is desirable when considering patient dosimetry.Tc-99m is readily available at relatively low cost throughcommercially-produced ⁹⁹Mo/Tc-99m generator systems. As a result, over80% of all radionuclide imaging studies conducted worldwide utilizeTc-99m. See generally Reedijk J. “Medicinal Applications of heavy-metalcompounds” Curr. Opin. Chem. Biol. (1999) 3(2): 236-240; and Hom, R. K.,Katzenellenbogen, J. A. “Technetium-99m-labeled receptor-specificsmall-molecule radiopharmaceuticals: recent developments and encouragingresults” Nuc. Med. and Biol. (1997) 24: 485-498. These advantages,coupled with the fact that Single Photon Emission Computed Tomographycameras are optimized for the 140 keV energy of Tc-99m, clearlydemonstrate the superiority of Tc-99m-labeled imaging agents.

Recently, a new Tc(I) labeling system has been developed. Aberto, R.,Schibli, R., Egli, A., Schubiger, A. P., Abram, U., Kaden, T. A. “ANovel Organometallic Aqua Complex of Technetium for the Labeling ofBiomolecules: Synthesis of [^(99m)Tc(OH₂)₃(CO)₃]⁺ from [^(99m)TcO₄]⁻ inAqueous Solution and Its Reaction with a Bifunctional Ligand” J. Am.Chem. Soc. (1998) 120: 7987-7988; and Alberto, R., Schibli, R., Daniela,A., Schubiger, A. P., Abram, U., Abram, S., Kaden, T. A. “Application oftechnetium and rhenium carbonyl chemistry to nuclearmedicine—Preparation of [Net₄]₂[TcCl₃(CO)₃] from [NBu₄][TcO₄] andstructure of [NEt₄][Tc₂(u-Cl)₃(CO)₆]; structures of the model complexes[NEt₄][Re₂(u-OEt)₂(u-OAc)(CO)₆] and [ReBr({—CH₂S(CH₂)₂Cl}₂(CO)₃]”Transition Met. Chem. (1997) 22: 597-601. This system takes advantage ofthe organometallic Tc(I) carbonyl chemistry. Importantly, the chemistryof [^(99m)Tc(OH₂)₃(CO)₃]⁺ has been elucidated and simplified to thepoint where the methods are routine and offer a practical alternative tothe currently employed Tc(V) chemistry. In contrast to the highlyreactive Tc(V)-oxo cores, where the chemistry is sometimes unpredictableand includes labeling cleanup steps, the Tc(I) method offers anattractive labeling alternative. However, unlike the Tc(V)-oxo core, theTc(I)(CO)₃ ⁺ core limits the number of possible coordination geometriesavailable for Tc due to the presence of the three carbonyl groups. Thefacial arrangement of carbonyl ligands around the metal center alsoimpose steric constraints on the binding possibilities of the remainingthree sites.

Moreover, the [^(99m)Tc(OH₂)₃(CO)₃]⁺ complex can be readily prepared insaline under 1 atm of carbon monoxide (CO). This water and air stableTc(I) complex is a practical precursor to highly inert Tc(I) complexes,due in part to the d⁶ electron configuration of the metal center. Asalready pointed out, the preparation of the organometallic tris(aquo)ion is simple and straightforward, allowing for convenient manipulationand product formation. Substitution of the labile H₂O ligands has beenshown to leave the Tc(CO)₃ ⁺ core intact. This stable core has theadditional advantage of being smaller and less polar than the routinelyemployed Tc(V)-oxo systems. This characteristic could be advantageous inbiologically relevant systems where the addition of the metal centereffects the size, shape, and potentially the bioactivity of thecompounds.

Although various chelators are currently employed in the binding oftechnetium, all of these tracers suffer from one or more disadvantageswhich render them less than ideal: HYNIC requires coligands; MAG3 may beonly used with the Tc(V)-oxo species; EDTA/DTPA is used primarily withTc(V)-oxo and its ability to retain label is poor. Hence, additionalTechnetium-99m chelators are needed. Novel radiolabeled chelators thatdisplay rapid, efficient labeling and demonstrate superior labelingretention for both Tc(V)-oxo and Tc(I)-tricarbonyl cores without the useof coligands are attractive candidates for clinical evaluation aspotential chelators for biologically relevant molecules.

SUMMARY OF THE INVENTION

Generally, this invention relates to complexes of a radionuclide withheteroaryl ligands, e.g., imidazolyl and pyridyl ligands, and their usein radiopharmaceuticals for a variety of clinical diagnostic andtherapeutic applications. Another aspect of the invention relates to,e.g., imidazolyl and pyridyl ligands that form a portion of theaforementioned complexes. Methods for the preparation of theradionuclide complexes are also described. Another aspect of theinvention relates to, e.g., imidazolyl and pyridyl ligands based onderivatized lysine, alanine and bis-amino acids for conjugation to smallpeptides by solid phase synthetic methods. Additionally, the inventionrelates to methods for imaging regions of a mammal using the complexesof the invention.

These embodiments of the present invention, other embodiments, and theirfeatures and characteristics, will be apparent from the description,drawings and claims that follow.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 depicts the structure of [Tc(CO)₃(L3a)].

FIG. 2 depicts the structure of [ReCl₃(L3a-ethylester)].

FIG. 3 depicts the structure of [Re(CO)₃(L1a-gly)].

FIG. 4 depicts the results of biodistribution studies.

DETAILED DESCRIPTION OF THE INVENTION 1. Overview

A class of radionuclide chelating agents based on the derivatization ofheteroaryl amines, such as di(imidizolylmethyl)amine (DIMA) anddi(pyridinemethyl)amine (DPMA) have been developed. Specificallydescribed here are the synthesis, radiolabeling, rhenium modeling, andtesting of novel radioactive dimethylimidazole and dimethylpyridinederivatives as bifunctional chelators which demonstrate a high bindingaffinity for Tc-99m, and have been derivatized to become biochemicalprobes for the assessment of a variety of biological processes, rangingfrom infection to cancer diagnosis. The structural features of atechnetium-99m labeled chelate have been optimized, such that agents aredeveloped which exhibit high labeling yield, superior retention and theversatility to label both Tc(V)-oxo and Tc(I)-tricarbonyl cores. Thecomplexes of the present invention allow labeling without the need forthe involvement of co-ligands. Eliminating the requirement for aco-ligand dramatically simplifies the labeling procedures of the presentinvention.

One aspect of the present invention involves the use ofdi(imidazolylmethyl)amine (DIMA) and analogs thereof as a tridentate orhigher dentate ligand for radionuclides. The ligand demonstratesremarkable ability to bind rapidly with Tc(I)-tricarbonyl cores.Notably, the neutral ligand may utilize three or more nitrogens asdonors to chelate the metal center.

The imidazole ring systems allow for extensive derivatization due to thepresence of a second heteroatom in the ring. This feature allows one toincrease lipophilicity and molecular size of the complex,characteristics that are beneficial for blood flow agents. Preliminaryresults in rats show high levels of accumulation in the heart with lowlevels in blood, lung and liver.

2. Four Classes of Chelates

Four specific classes of imidazole and benzimidazole chelates aredefined below. Based on this disclosure, one of ordinary skill in theart will be able to envision other classes of imidazole chelate, all ofwhich are hereby expressly embraced by the disclosure. Each enumeratedclass may be used to form cationic metal complexes and in some casesneutral metal complexes depending on the metal used. The metals ofinterest include: for nuclear medicine applications, technetium(Tc-99m), rhenium (Re-188, Re-186), gallium (Ga-68), copper (Cu-62,Cu-64), and for MRI applications gadolinum, iron (Fe³⁺ and Fe²⁺), andmanganese. The classes are as follows:

Class I: Tridentate di-imidazole(di-benzimidazole)amine

This tridentate class of chelates offers flexibility of thelipophilicity of the chelate by modulating the lipophilic nature of R₂.R₁ may be altered to supply a ligating anionic molecule to vary thecharge of the complex, and it may also be a biologically relevantmolecule.

Class II: Hexadentate tetra-imidazole (tetra-benzimidazole)diamine

This “dimeric” extension of class I offers hexacoordination.

Class III: Hexadentate di-imidazole (di-benzimidazole)di-substituteddiamine

This class is similar to Class II in that it is hexadentate, but itoffers more flexibility as to the net charge which can be adjustedthrough the choice of the non-imidazole arms, R₃. R₃ can beindependently altered to introduce anionic ligating groups, such ascarboxylate, thiolate, or phenolic substituents. Neutral ligands, suchas pyridine, may also be used as R₃. In this class, R₂ can be used tomodulate lipophilicity and R₃ can be used to modulate charge. R₃ mayalso be used to modulate lipophilicity if used with non-coordinatinggroups, such as ethers, alkylaryl, or aralkyl groups. R₃ may be the sameor different.

Class IV: Hexa- and octa-coordinatepolyimidazole(polybenzimidazole)triamines

This class offers hexa-coordination or octa-coordination. Flexibility asto the net charge can be obtained through choice of the none-imidazolearms R₃ and R₁. R₃ and R₁ can be altered to introduce anionic ligatinggroups, such as carboxylate, thiolate or phenolic substituents. Neutralligands, such as pyridine, may also be used or mixed with anionicligands for the desired net ligand charge. Lipophilicity may bemodulated through R₂, R₃, and R₁ depending on desired charge. R₃ and R₁may also be used to modulate lipophilicity if used with non-coordinatinggroups, such as ethers, alkylaryl, or aralkyl groups. R₃ or R₁ may alsobe a biologically-relevant molecule.

In one embodiment, the basic structure is a di-imidazole on a triaminebackbone. The simplest embodiment would be penta-coordinate ligand,where R₃ is not ligating. The highest coordination would be 8 where R₃and R₁ contain ligating groups. Ligand charge may vary from −3 to zero.Table 1 summarizes possible chelating modes and properties that may beobtained with a class IV chelate.

TABLE 1 Summary of possible chelating modes and properties for class IVchelates. Other Potential Com- “Imidazole” ligating Potential ligandpound groups N(aliphatic) groups coordination charge a 2 3 1 6 −1 to 0 b2 3 2 7 −2 to 0 c 2 3 3 8 −3 to 0 d 3 3 0 6 0 e 3 3 2 8 −2 to 0 f 4 3 07 0 g 4 3 1 8 −1 to 0 h 5 3 0 8 0

3. Ligands for Radionuclides

One aspect of the present invention involves the use ofdi(imidazolemethyl)amine as a tridentate ligand for radionuclides. Theligand demonstrates remarkable ability to rapidly bind both Tc(V)-oxoand Tc(I)-tricarbonyl cores. Notably, the neutral ligand utilizes allthree nitrogens as donors to chelate the metal center.

Moreover, a biologically relevant molecule, e.g., a peptide or DATligand, can be covalently linked to the central nitrogen of the ligandwithout interfering with the ligand's ability to chelate theradionuclide. The following drawing depicts this embodiment, wherein Rrepresents a biologically relevant molecule.

Chelators based on these ligands serve as neutral, i.e., uncharged,tridentate (N—N—N) donors for both the Tc(V)-oxo and Tc(I)-tricarbonylcores. However, ligands can also be prepared that are cationic oranionic, e.g., depending on the charge of the group attached to thecentral nitrogen in the structures above. Additionally, the variousclasses of ligands shown below may be used with the Tc(I)-tricarbonylcore. Some examples are presented below.

Another aspect of the present invention relates to development of novelTc-99m labeled analogs, and evaluation of their potential as myocardialblood flow imaging agents (e.g., investigation as potential heartimaging agents in rats). The rationale behind these studies is that thechelate is small, lipophilic, and potentially cationic at physiologicalpH, all of which are characteristics of effective blood flow agents.

A major concern when designing a chelated-Tc-99m labeled pharmaceuticalis that the inclusion of the Tc-ligand in the carrier molecule shouldnot drastically alter the biological behavior of the carrier. See Horn,R. K., Katzenellenbogen, J. A. “Technetium-99m-labeled receptor-specificsmall-molecule radiopharmaceuticals: recent developments and encouragingresults” Nuc. Med. and Biol. (1997) 24: 485-498. In these labelingapproaches, the chelated radionuclide is bound to the bio-molecule via apendant chain distant to the receptor-binding site. Advantages of thisdesign include the ability to change the length and location of thependant chain, as well as the ability to vary chelating moieties. Byadopting these ideas one may quickly synthesize a series of versatilechelators that could be functionalized with various biologicalmolecules. Scheme 1 depicts the synthesis of various derivatives.

This work lead to the design of bifunctional chelators constructed fromamino acids, so as to provide a donor set for effective coordination ofTc(I) and a linker group for attachment to peptide units. Thesignificance of this ligand design is that the bifunctional chelatorsmay be developed as reagents for direct incorporation into conventionalsolid phase peptide syntheses (SPPS), thus exploiting the considerableadvantages in purity, cost, scale and design afforded by SPPS.

In a preliminary study, the related alanine derivative(bis-2-pyridylmethylamino-ethylcarboxylic acid, L3a) was prepared by themethods described below. The Tc(I) complex of L3a [Tc(CO)₃(L3a)] wasprepared in nearly quantitative yield, as well as an unusual materialexhibiting the rhenium(IV)-trichloride core [ReCl₃(L3a-ethylester)]. Thefacile preparations of these model compounds suggested that a family ofbifunctional chelators, derived from simple amino acids or bis-aminoacids could be developed, which through suitable manipulation of theligand donor groups can provide neutral, cationic or anionic Tc(I)complexes.

One goal of the present invention is to develop a family of bifunctionalchelators based on quinoline or isoquinoline and/or carboxylatederivatized amino acids or bis-amino acids for conjugation to smallpeptides by solid phase synthetic methods. To achieve this, lysine,alanine, aminoalanine and a series of bis amino acids are modified toincorporate a tridentate chelation terminus, as well as a terminus forconjugation to small peptides exploiting solid phase synthesis. Theoptimal design of the tether is also investigated. In certainembodiments, the present invention relates to amino acids, e.g.,alpha-amino acids, bearing covalently linked bifunctional chelators forradionuclides, e.g., technetium. For example, the present inventionrelates to compounds represented by scheme 2, wherein R represents acovalent tether, e.g., a butylene linker as in Lys, between the alphacarbon of the alpha-amino acid and a bifunctional chelator of theinstant invention for a radionuclide. Amino acids, such as those inscheme 2, bearing a bifunctional chelator for a radionuclide may be usedin place of natural amino acids in any of the methods of oligopeptide,polypeptide or protein synthesis, including the methods of automatedprotein synthesis.

4. Design and Synthesis of Bifunctional Chelates

The “organometallic approach” for functionalization and radiolabeling oftarget specific biomolecules, pioneered by Jaouen, has receivedconsiderable attention in recent years. Salmain, M.; Gunn, M.; Gorfe,A.; Top, S.; Jaouen, G. Bioconjugate Chem. 1993, 4, 425. In particular,Tc(I)- and Re(I)-tricarbonyl complexes are ideal candidates for thelabeling of receptor avid biomolecules in terms of reduced size andkinetic inertness of their complexes. The {M(CO)₃}⁺¹ core exhibitsparticular affinity for nitrogen and oxygen donor ligands and formsrobust complexes with such tridentate N,O donor ligands of the generaltype [M(CO)₃(N_(x)O_(3-x))], where N_(x)O_(3-x) is the tridentatechelator. This observation provides the conceptual starting point forthe design of our bifunctional chelates for peptide labeling.

As illustrated below in Scheme 3, certain bifunctional chelates arederived from lysine, alanine, aminoalanine or bis-amino acids. Sinceboth the identity of the donor groups and the amino acid backbone can bereadily modified, the chelator and the linker termini may be optimizedfor ^(99m)Tc coordination and peptide conjugation, respectively.Furthermore, by modifying the identities of the chelating donor groups,neutral, anionic and cationic complexes of general types [M(CO)₃(L1a)],[M(CO)₃(L1b)]⁻ and [M(CO)₃(L1c)]⁺ may be prepared for differentapplications. Representative ligand syntheses are detailed below forL1c-Boc and L2d-Boc, illustrating the direct and facile methodology.Moreover, any instance of Het may be an imidazolyl moiety or otherheteroaryl moiety (e.g. quinoline, isoquinoline, benzimdazole, etc.) notexpressly depicted below in Schemes 3 and 4.

At this stage, conventional solid-phase synthesis can be exploited toprepare the peptide conjugate. Bodansky, M., Principles of PeptideSynthesis, Springer-Verlag: Berlin, 1984; and Bodansky, M.; Bodansky,A., The Practice of Peptide Synthesis, Springer-Verlag: Berlin, 1984.The peptide chain can be constructed using FMOC protocols and cappedwith a BOC protecting group. The bifunctional chelator (BFC) may now beintroduced to provide a pendant peptide-BFC design. Alternatively, thebis-amino acid based BFCs may be incorporated into the peptide sequenceto provide a variant of the integrated design concept (Scheme 5).

5. Synthesis of Rhenium Analogs for Structural Characterization

Many of the properties of the Group VII metals technetium and rheniumare similar. It is anticipated that the metals will demonstrate similarreaction chemistry, which is often the case for the thiol, nitrogen,phosphine and oxo-chemistry of these two metals. Likewise, perrhenateand pertechnetate have very similar reaction behaviors. Rose, D. J.,Maresca, K. P., Nicholson, T., Davison, A., Jones, A. G., Babich, J.,Fischman, A., Graham, W., DeBord, J. R. D., Zubieta, J. “Synthesis andCharacterization of Organohydrazine Complexes of Technetium, Rhenium,and Molybdenum with the {M(η1-HxNNR)(η2-HyNNR)} Core and TheirRelationship to Radiolabeled Organohydrazine-Derivatized ChemotacticPeptides with Diagnostic Applications” Inorg. Chem. (1998) 37:2701-2716. The similar reductions of the M(VII) oxo species by SnCl₂allowed for easy substitution of the nonradioactive rhenium as a modelfor the medicinally useful technetium-99m, which routinely usestin-reduced ^(99m)Tc. Synthesizing the rhenium-diimidazolemethylamineand rhenium-dipyridinemethylamine complexes provided a facile route tostructurally characterize the products. The characterized products may,in turn, lead to the development of new Tc-DIMA and Tc-DPMA derivativesbased on the presence or absence of a structural feature observed in therhenium data. The periodic relationship between Tc and Re indicates thatTc-99m radiopharmaceuticals can be designed by modeling analogousrhenium complexes. Nicholson, T., Cook, J., Davison, A., Rose, D. J.,Maresca K. P., Zubieta, J. A., Jones, A. G. “The synthesis andcharacterization of [MCl₃(N═NC₅H₄NH)(HN═NC₅H₄N)] from [MO₄]⁻ (whereM=Re, Tc) organodiazenido, organodiazene-chelate complexes” Inorg. Chim.Acta (1996) 252: 421-426. The coordination chemistry with{Re(CO)₃(H₂O)₃}⁺ has produced a number of derivatives including themodel compound [Re(CO)₃(L1a-gly)] (4), shown in FIG. 3.

Re(V)-Oxo Core

The synthesis of the rhenium analogs followed the established chemistryof the N₂S₂ system in forming stable, neutral, rhenium-oxo complexes.Davison A, Jones A G, Orvig C, et al: “A new class of oxotechnetium (5+)chelate complexes containing a TcON₂S₂ core” Inorg. Chem. 20: 1629-1631,1981; Kung H F, Guo Y-Z, Mach R H, et al: “New Tc-99 complexes based onN₂S₂ ligands” J. Nucl. Med. 27: 1051, 1986 (abstr.); Kung H F, Molnar M,Billings J, et al: “Synthesis and biodistribution of neutrallipid-soluble Tc-99m complexes that cross the blood-brain barrier” J.Nucl. Med. 25: 326-332, 1984; and Kung H F, Yu C C, Billings J, et al:“Synthesis of new bis(aminoethanethiol) (BAT) derivatives: Possibleligands for ^(99m)Tc brain imaging agents” J. Med. Chem. 28: 1280-1284,1985. The N₃ systems of the present invention, with three nitrogendonors forms a predictablable metal-complex with an overall net chargeof zero. The synthesis of the Re(III) complexes was accomplished byreacting [TBA][ReOBr₄(OPPh₃)] with the appropriate ligand in the ratioof 1:1.2 in 10 mL of methanol and three equivalents of NEt₃ as base. Thereaction was allowed to reflux for roughly ½ hour. After cooling, thereaction products were be purified using a small column using the methodestablished by Spies and co-workers. Spies, H., Fietz, T., Glaser, M.,Pietzsch, H.-J., Johannsen, B. In “Technetium and Rhenium in Chemistryand Nuclear Medicine 3”, Nicollini, M., Bandoli, G., Mazzi, U., eds.,Padova, Italy, 1995, 4, 243. Alternatively, the rhenium (V) startingmaterial [ReOCl₃(PPh₃)₂] may be employed as the potential rheniumstarting material. This versatile material has proven successful in thepast for dealing with nitrogen and sulfur donor atoms. Maresca, K. P.,Femia, F. J., Bonavia, G. H., Babich, J. W., Zubieta, J. “Cationiccomples of the ‘3+1’ oxorhenium-thiolate complexes” Inorganic ChemistryActa (2000) 297: 98-105; and Maresca, K. P., Rose, D. J., Zubieta, J.“Synthesis and characterization of a binuclear rhenium nitropyrazole”Inorganica Chimica Acta (1997) 260: 83-88. The synthesized rhenium-DIMAand rhenium-DPMA complexes have been run through a HPLC column forseparation and purification purposes following the procedures describedfor the technetium complexes. The complexes were then analyzed byelemental analysis, infrared spectroscopy, mass spectroscopy, and NMRspectroscopy.

Re(I)(CO)₃ ⁺ Core

The Re(I)(CO)3⁺ system displays similar reaction chemistry to that ofthe Tc-99m tricarbonyl core. The use of [NEt₄]₂[ReBr₃(CO)₃], as thestarting material leads to easy formation of the fac-Re(CO)₃(L)₃ core.The [NEt₄]₂[ReBr₃(CO)₃] is readily derived from the [ReBr(CO)₅]. Thesynthesis of the Re(I) complexes has been accomplished by reacting[NEt₄]₂[ReBr₃(CO)₃] with the appropriate DIMA or DPMA ligand in theratio of 1:1.2 in 10 mL of H₂O and three equivalents of NEt₃ as base.The reaction was allowed to heat at 80-130° C. for 4 hours. Aftercooling, the reaction products were purified using a small column usingthe method established by Alberto and coworkers. Spies, H., Fietz, T.,Glaser, M., Pietzsch, H.-J., Johannsen, B. In “Technetium and Rhenium inChemistry and Nuclear Medicine 3”, Nicollini, M., Bandoli, G., Mazzi,U., eds., Padova, Italy, 1995, 4, 243. This versatile material hasproven successful in the past for dealing with nitrogen and oxygen donoratoms. The synthesized rhenium-DIMA and rhenium-DPMA complexes were thenrun through a HPLC column for separation and purification purposes,following the procedures previously described for the technetiumcomplexes. Next, the complexes were analyzed by: elemental analysis,infrared spectroscopy, mass spectroscopy, and NMR spectroscopy.

The stability and robustness of the technetium-di(pyridine) complexeswas assessed using challenges with free cysteine and histidine.Specifically, the experiments were performed using[^(99m)Tc(CO)₃(dipyridinemethylamine)]⁺¹. The complex was found to bestable in the face of relatively high concentrations of these aminoacids. For example, HPLC analyses showed no significant change in thecomponents when an aqueous solution of the complex was incubated withcysteine for 18 hours at 37° C. at pH 7.4.

The synthesis and use as ligands for metal tricarbonyls, e.g., Re and Tctricarbonyls, protected and unprotected versions of[ε-{N,N-di(pyridyl-2-methyl)}α-(fmoc)lysine] (Fmoc-DpK) has also beeninvestigated. The choice of the tridentate DpK for the exploration of asingle amino acid chelate was based on the excellent RCP and RCY, andthe potential to prepare radiopharmaceutical kits. Thepyridine-2-methylamine was easily derivatized into the amino acid. Thebiodistribution results showed [^(99m)Tc(CO)₃(DpK)] having rapid bloodclearance with % ID/g=0.6 at 5 minutes to % ID/g=0.07 by 30 minutes.

This approach enables the creation of libraries containing the{M(CO)₃}¹⁺ core. We have begun to define the biological fate of the^(99m)Tc-dipyridine complexes, allowing us to compare a series of futuretridentate analogs. The dipyridine labeling proceeded in high yield andwas stable to excess histidine and cysteine challenges for more than 18hours. Biodistribution studies showed major accumulation in kidney andliver only, at early timepoints. Activity decreased in all tissues as afunction of time, except in the GI tract, which increased with time.These experiments suggest that dipyridine is a potential enablingtechnology for the labeling of important biomolecules.

6. Definitions

For convenience, before further description of the present invention,certain terms employed in the specification, examples, and appendedclaims are collected here.

The articles “a” and “an” are used herein to refer to one or to morethan one (i.e., to at least one) of the grammatical object of thearticle. By way of example, “an element” means one element or more thanone element.

The terms “comprise” and “comprising” are used in the inclusive, opensense, meaning that additional elements may be included.

The term “including” is used herein to mean “including but not limitedto”. “Including” and “including but not limited to” are usedinterchangeably.

The terms “lipophilic group” and “lipophilic moiety” as used hereinrefer to a group, moiety or substituent that has a greater affinity fornon-polar or non-aqueous environments versus polar or aqueousenvironments. For example, Merriam Webster's online dictionary defines“lipophilic” as “having an affinity for lipids (as fats).” Exemplarylipophilic moieties include aliphatic hydrocarbon radicals, e.g., alkylradicals, aromatic hydrocarbon radicals, and long-chain acyl radicals;all of them have increasing lipophilicity as the number of constituentcarbons increases. In general, addition of a lipophilic moiety to aparticular compound will increase the compound's affinity for octanol inthe standard octanol/water partition-coefficient-determination protocol;this protocol may be used to gauge a compound's relative hydrophobicity(lipophilicity) and hydrophilicity.

The terms “Lewis base” and “Lewis basic” are art-recognized andgenerally refer to a chemical moiety capable of donating a pair ofelectrons under certain reaction conditions. It may be possible tocharacterize a Lewis base as donating a single electron in certaincomplexes, depending on the identity of the Lewis base and the metalion, but for most purposes, however, a Lewis base is best understood asa two electron donor. Examples of Lewis basic moieties include unchargedcompounds such as alcohols, thiols, and amines, and charged moietiessuch as alkoxides, thiolates, carbanions, and a variety of other organicanions. In certain examples, a Lewis base may consist of a single atom,such as oxide (O₂ ⁻) In certain, less common circumstances, a Lewis baseor ligand may be positively charged. A Lewis base, when coordinated to ametal ion, is often referred to as a ligand. Further description ofligands relevant to the present invention is presented herein.

The term “ligand” is art-recognized and refers to a species thatinteracts in some fashion with another species. In one example, a ligandmay be a Lewis base that is capable of forming a coordinate bond with aLewis Acid. In other examples, a ligand is a species, often organic,that forms a coordinate bond with a metal ion. Ligands, when coordinatedto a metal ion, may have a variety of binding modes know to those ofskill in the art, which include, for example, terminal (i.e., bound to asingle metal ion) and bridging (i.e., one atom of the Lewis base boundto more than one metal ion).

The term “chelating agent” is art-recognized and refers to a molecule,often an organic one, and often a Lewis base, having two or moreunshared electron pairs available for donation to a metal ion. The metalion is usually coordinated by two or more electron pairs to thechelating agent. The terms, “bidentate chelating agent”, “tridentatechelating agent”, and “tetradentate chelating agent” are art-recognizedand refer to chelating agents having, respectively, two, three, and fourelectron pairs readily available for simultaneous donation to a metalion coordinated by the chelating agent. Usually, the electron pairs of achelating agent forms coordinate bonds with a single metal ion; however,in certain examples, a chelating agent may form coordinate bonds withmore than one metal ion, with a variety of binding modes being possible.

The term “coordination” is art-recognized and refers to an interactionin which one multi-electron pair donor coordinatively bonds (is“coordinated”) to one metal ion.

The term “complex” is art-recognized and refers to a compound formed bythe union of one or more electron-rich and electron-poor molecules oratoms capable of independent existence with one or more electronicallypoor molecules or atoms, each of which is also capable of independentexistence.

The term “tether” is art-recognized and refers to, as used herein, achemical linking moiety between a metal ion center and another chemicalmoiety.

The term “amino acid” is art-recognized and refers to all compounds,whether natural or synthetic, which include both an amino functionalityand an acid functionality, including amino acid analogs and derivatives.

The term “heteroatom” is art-recognized and refers to an atom of anyelement other than carbon or hydrogen. Illustrative heteroatoms includeboron, nitrogen, oxygen, phosphorus, sulfur and selenium.

The term “alkyl” is art-recognized, and includes saturated aliphaticgroups, including straight-chain alkyl groups, branched-chain alkylgroups, cycloalkyl (alicyclic) groups, alkyl substituted cycloalkylgroups, and cycloalkyl substituted alkyl groups. In certain embodiments,a straight chain or branched chain alkyl has about 30 or fewer carbonatoms in its backbone (e.g., C₁-C₃₀ for straight chain, C₃-C₃₀ forbranched chain), and alternatively, about 20 or fewer. Likewise,cycloalkyls have from about 3 to about 10 carbon atoms in their ringstructure, and alternatively about 5, 6 or 7 carbons in the ringstructure.

Unless the number of carbons is otherwise specified, “lower alkyl”refers to an alkyl group, as defined above, but having from one to aboutten carbons, alternatively from one to about six carbon atoms in itsbackbone structure. Likewise, “lower alkenyl” and “lower alkynyl” havesimilar chain lengths.

The term “aralkyl” is art-recognized and refers to an alkyl groupsubstituted with an aryl group (e.g., an aromatic or heteroaromaticgroup).

The terms “alkenyl” and “alkynyl” are art-recognized and refer tounsaturated aliphatic groups analogous in length and possiblesubstitution to the alkyls described above, but that contain at leastone double or triple bond respectively.

The term “aryl” is art-recognized and refers to 5-, 6- and 7-memberedsingle-ring aromatic groups that may include from zero to fourheteroatoms, for example, benzene, naphthalene, anthracene, pyrene,pyrrole, furan, thiophene, imidazole, oxazole, thiazole, triazole,pyrazole, pyridine, pyrazine, pyridazine and pyrimidine, and the like.Those aryl groups having heteroatoms in the ring structure may also bereferred to as “aryl heterocycles” or “heteroaromatics.” The aromaticring may be substituted at one or more ring positions with suchsubstituents as described above, for example, halogen, azide, alkyl,aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxyl, amino, nitro,sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl,silyl, ether, alkylthio, sulfonyl, sulfonamido, ketone, aldehyde, ester,heterocyclyl, aromatic or heteroaromatic moieties, —CF₃, —CN, or thelike. The term “aryl” also includes polycyclic ring systems having twoor more cyclic rings in which two or more carbons are common to twoadjoining rings (the rings are “fused rings”) wherein at least one ofthe rings is aromatic, e.g., the other cyclic rings may be cycloalkyls,cycloalkenyls, cycloalkynyls, aryls and/or heterocyclyls.

The terms ortho, meta and para are art-recognized and refer to 1,2-,1,3- and 1,4-disubstituted benzenes, respectively. For example, thenames 1,2-dimethylbenzene and ortho-dimethylbenzene are synonymous.

The terms “heterocyclyl”, “heteroaryl”, or “heterocyclic group” areart-recognized and refer to 3- to about 10-membered ring structures,alternatively 3- to about 7-membered rings, whose ring structuresinclude one to four heteroatoms. Heterocycles may also be polycycles.Heterocyclyl groups include, for example, thiophene, thianthrene, furan,pyran, isobenzofuran, chromene, xanthene, phenoxanthene, pyrrole,imidazole, pyrazole, isothiazole, isoxazole, pyridine, pyrazine,pyrimidine, pyridazine, indolizine, isoindole, indole, indazole, purine,quinolizine, isoquinoline, quinoline, phthalazine, naphthyridine,quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline,phenanthridine, acridine, pyrimidine, phenanthroline, phenazine,phenarsazine, phenothiazine, furazan, phenoxazine, pyrrolidine, oxolane,thiolane, oxazole, piperidine, piperazine, morpholine, lactones, lactamssuch as azetidinones and pyrrolidinones, sultams, sultones, and thelike. The heterocyclic ring may be substituted at one or more positionswith such substituents as described above, as for example, halogen,alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, amino, nitro,sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl,silyl, ether, alkylthio, sulfonyl, ketone, aldehyde, ester, aheterocyclyl, an aromatic or heteroaromatic moiety, —CF₃, —CN, or thelike.

The terms “polycyclyl” or “polycyclic group” are art-recognized andrefer to two or more rings (e.g., cycloalkyls, cycloalkenyls,cycloalkynyls, aryls and/or heterocyclyls) in which two or more carbonsare common to two adjoining rings, e.g., the rings are “fused rings”.Rings that are joined through non-adjacent atoms are termed “bridged”rings. Each of the rings of the polycycle may be substituted with suchsubstituents as described above, as for example, halogen, alkyl,aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, amino, nitro,sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl,silyl, ether, alkylthio, sulfonyl, ketone, aldehyde, ester, aheterocyclyl, an aromatic or heteroaromatic moiety, —CF₃, —CN, or thelike.

The term “carbocycle” is art-recognized and refers to an aromatic ornon-aromatic ring in which each atom of the ring is carbon.

The term “nitro” is art-recognized and refers to —NO₂; the term“halogen” is art-recognized and refers to —F, —Cl, —Br or —I; the term“sulfhydryl” is art-recognized and refers to —SH; the term “hydroxyl”means —OH; and the term “sulfonyl” is art-recognized and refers to —SO₂⁻. “Halide” designates the corresponding anion of the halogens, and“pseudohalide” has the definition set forth on 560 of “AdvancedInorganic Chemistry” by Cotton and Wilkinson.

The terms “amine” and “amino” are art-recognized and refer to bothunsubstituted and substituted amines, e.g., a moiety that may berepresented by the general formulas:

wherein R50, R51 and R52 each independently represent a hydrogen, analkyl, an alkenyl, —(CH₂)_(m)—R61, or R50 and R51, taken together withthe N atom to which they are attached complete a heterocycle having from4 to 8 atoms in the ring structure; R61 represents an aryl, acycloalkyl, a cycloalkenyl, a heterocycle or a polycycle; and m is zeroor an integer in the range of 1 to 8. In other embodiments, R50 and R51(and optionally R52) each independently represent a hydrogen, an alkyl,an alkenyl, or —(CH₂)_(m)—R61. Thus, the term “alkylamine” includes anamine group, as defined above, having a substituted or unsubstitutedalkyl attached thereto, i.e., at least one of R50 and R51 is an alkylgroup.

The term “acylamino” is art-recognized and refers to a moiety that maybe represented by the general formula:

wherein R50 is as defined above, and R54 represents a hydrogen, analkyl, an alkenyl or —(CH₂)_(m)—R61, where m and R61 are as definedabove.

The term “amido” is art recognized as an amino-substituted carbonyl andincludes a moiety that may be represented by the general formula:

wherein R50 and R51 are as defined above. Certain embodiments of theamide in the present invention will not include imides which may beunstable.

The term “alkylthio” refers to an alkyl group, as defined above, havinga sulfur radical attached thereto. In certain embodiments, the“alkylthio” moiety is represented by one of —S-alkyl, —S-alkenyl,—S-alkynyl, and —S—(CH₂)_(m)—R61, wherein m and R61 are defined above.Representative alkylthio groups include methylthio, ethyl thio, and thelike.

The term “carboxyl” is art recognized and includes such moieties as maybe represented by the general formulas:

wherein X50 is a bond or represents an oxygen or a sulfur, and R55 andR56 represents a hydrogen, an alkyl, an alkenyl, —(CH₂)_(m)—R61 or apharmaceutically acceptable salt, R56 represents a hydrogen, an alkyl,an alkenyl or —(CH₂)_(m)—R61, where m and R61 are defined above. WhereX50 is an oxygen and R55 or R56 is not hydrogen, the formula representsan “ester”. Where X50 is an oxygen, and R55 is as defined above, themoiety is referred to herein as a carboxyl group, and particularly whenR55 is a hydrogen, the formula represents a “carboxylic acid”. Where X50is an oxygen, and R56 is hydrogen, the formula represents a “formate”.In general, where the oxygen atom of the above formula is replaced bysulfur, the formula represents a “thiolcarbonyl” group. Where X50 is asulfur and R55 or R56 is not hydrogen, the formula represents a“thiolester.” Where X50 is a sulfur and R55 is hydrogen, the formularepresents a “thiolcarboxylic acid.” Where X50 is a sulfur and R56 ishydrogen, the formula represents a “thiolformate.” On the other hand,where X50 is a bond, and R55 is not hydrogen, the above formularepresents a “ketone” group. Where X50 is a bond, and R55 is hydrogen,the above formula represents an “aldehyde” group.

The term “carbamoyl” refers to —O(C═O)NRR′, where R and R′ areindependently H, aliphatic groups, aryl groups or heteroaryl groups.

The term “oxo” refers to a carbonyl oxygen (═O).

The terms “oxime” and “oxime ether” are art-recognized and refer tomoieties that may be represented by the general formula:

wherein R75 is hydrogen, alkyl, cycloalkyl, alkenyl, alkynyl, aryl,aralkyl, or —(CH₂)_(m)—R61. The moiety is an “oxime” when R is H; and itis an “oxime ether” when R is alkyl, cycloalkyl, alkenyl, alkynyl, aryl,aralkyl, or —(CH₂)_(m)—R61.

The terms “alkoxyl” or “alkoxy” are art-recognized and refer to an alkylgroup, as defined above, having an oxygen radical attached thereto.Representative alkoxyl groups include methoxy, ethoxy, propyloxy,tert-butoxy and the like. An “ether” is two hydrocarbons covalentlylinked by an oxygen. Accordingly, the substituent of an alkyl thatrenders that alkyl an ether is or resembles an alkoxyl, such as may berepresented by one of —O-alkyl, —O-alkenyl, —O-alkynyl,—O—(CH₂)_(m)—R61, where m and R61 are described above.

The term “sulfonate” is art recognized and refers to a moiety that maybe represented by the general formula:

in which R57 is an electron pair, hydrogen, alkyl, cycloalkyl, or aryl.

The term “sulfate” is art recognized and includes a moiety that may berepresented by the general formula:

in which R57 is as defined above.

The term “sulfonamido” is art recognized and includes a moiety that maybe represented by the general formula:

in which R50 and R56 are as defined above.

The term “sulfamoyl” is art-recognized and refers to a moiety that maybe represented by the general formula:

in which R50 and R51 are as defined above.

The term “sulfonyl” is art-recognized and refers to a moiety that may berepresented by the general formula:

in which R58 is one of the following: hydrogen, alkyl, alkenyl, alkynyl,cycloalkyl, heterocyclyl, aryl or heteroaryl.

The term “sulfoxido” is art-recognized and refers to a moiety that maybe represented by the general formula:

in which R58 is defined above.

The term “phosphoryl” is art-recognized and may in general berepresented by the formula:

wherein Q50 represents S or O, and R59 represents hydrogen, a loweralkyl or an aryl. When used to substitute, e.g., an alkyl, thephosphoryl group of the phosphorylalkyl may be represented by thegeneral formulas:

wherein Q50 and R59, each independently, are defined above, and Q51represents O, S or N. When Q50 is S, the phosphoryl moiety is a“phosphorothioate”.

The term “phosphoramidite” is art-recognized and may be represented inthe general formulas:

wherein Q51, R50, R51 and R59 are as defined above.

The term “phosphonamidite” is art-recognized and may be represented inthe general formulas:

wherein Q51, R50, R51 and R59 are as defined above, and R60 represents alower alkyl or an aryl.

Analogous substitutions may be made to alkenyl and alkynyl groups toproduce, for example, aminoalkenyls, aminoalkynyls, amidoalkenyls,amidoalkynyls, iminoalkenyls, iminoalkynyls, thioalkenyls, thioalkynyls,carbonyl-substituted alkenyls or alkynyls.

The definition of each expression, e.g. alkyl, m, n, and the like, whenit occurs more than once in any structure, is intended to be independentof its definition elsewhere in the same structure.

The term “selenoalkyl” is art-recognized and refers to an alkyl grouphaving a substituted seleno group attached thereto. Exemplary“selenoethers” which may be substituted on the alkyl are selected fromone of —Se-alkyl, —Se-alkenyl, —Se-alkynyl, and —Se—(CH₂)_(m)—R61, m andR61 being defined above.

The terms triflyl, tosyl, mesyl, and nonaflyl are art-recognized andrefer to trifluoromethanesulfonyl, p-toluenesulfonyl, methanesulfonyl,and nonafluorobutanesulfonyl groups, respectively. The terms triflate,tosylate, mesylate, and nonaflate are art-recognized and refer totrifluoromethanesulfonate ester, p-toluenesulfonate ester,methanesulfonate ester, and nonafluorobutanesulfonate ester functionalgroups and molecules that contain said groups, respectively.

The abbreviations Me, Et, Ph, Tf, Nf, Ts, and Ms represent methyl,ethyl, phenyl, trifluoromethanesulfonyl, nonafluorobutanesulfonyl,p-toluenesulfonyl and methanesulfonyl, respectively. A morecomprehensive list of the abbreviations utilized by organic chemists ofordinary skill in the art appears in the first issue of each volume ofthe Journal of Organic Chemistry; this list is typically presented in atable entitled Standard List of Abbreviations.

Certain compounds contained in compositions of the present invention mayexist in particular geometric or stereoisomeric forms. In addition,polymers of the present invention may also be optically active. Thepresent invention contemplates all such compounds, including cis- andtrans-isomers, R- and S-enantiomers, diastereomers, (D)-isomers,(L)-isomers, the racemic mixtures thereof, and other mixtures thereof,as falling within the scope of the invention. Additional asymmetriccarbon atoms may be present in a substituent such as an alkyl group. Allsuch isomers, as well as mixtures thereof, are intended to be includedin this invention.

If, for instance, a particular enantiomer of compound of the presentinvention is desired, it may be prepared by asymmetric synthesis, or byderivation with a chiral auxiliary, where the resulting diastereomericmixture is separated and the auxiliary group cleaved to provide the puredesired enantiomers. Alternatively, where the molecule contains a basicfunctional group, such as amino, or an acidic functional group, such ascarboxyl, diastereomeric salts are formed with an appropriateoptically-active acid or base, followed by resolution of thediastereomers thus formed by fractional crystallization orchromatographic means well known in the art, and subsequent recovery ofthe pure enantiomers.

It will be understood that “substitution” or “substituted with” includesthe implicit proviso that such substitution is in accordance withpermitted valence of the substituted atom and the substituent, and thatthe substitution results in a stable compound, e.g., which does notspontaneously undergo transformation such as by rearrangement,cyclization, elimination, or other reaction.

The term “substituted” is also contemplated to include all permissiblesubstituents of organic compounds. In a broad aspect, the permissiblesubstituents include acyclic and cyclic, branched and unbranched,carbocyclic and heterocyclic, aromatic and nonaromatic substituents oforganic compounds. Illustrative substituents include, for example, thosedescribed herein above. The permissible substituents may be one or moreand the same or different for appropriate organic compounds. Forpurposes of this invention, the heteroatoms such as nitrogen may havehydrogen substituents and/or any permissible substituents of organiccompounds described herein which satisfy the valences of theheteroatoms. This invention is not intended to be limited in any mannerby the permissible substituents of organic compounds.

The phrase “protecting group” as used herein means temporarysubstituents which protect a potentially reactive functional group fromundesired chemical transformations. Examples of such protecting groupsinclude esters of carboxylic acids, silyl ethers of alcohols, andacetals and ketals of aldehydes and ketones, respectively. The field ofprotecting group chemistry has been reviewed (Greene, T. W.; Wuts, P. G.M. Protective Groups in Organic Synthesis, 3^(rd) ed.; Wiley: New York,1999). Protected forms of the inventive compounds are included withinthe scope of this invention.

For purposes of this invention, the chemical elements are identified inaccordance with the Periodic Table of the Elements, CAS version,Handbook of Chemistry and Physics, 67th Ed., 1986-87, inside cover.

7. Compounds and Methods of the Invention

In one aspect, the present invention relates to a compound of formula A:

wherein, independently for each occurrence,

R¹ is H, alkyl, hydroxyalkyl, alkoxyalkyl, aminoalkyl, thioalkyl,alkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl, acyl,aminoacyl, hydroxyacyl, thioacyl, (amino)alkoxycarbonyl,(hydroxy)alkoxycarbonyl, (amino)alkylaminocarbonyl,(hydroxy)alkylaminocarbonyl, —CO₂H, —(CH₂)_(d)—R₈₀, or an amino acidradical;

R₈₀ is carboxaldehyde, carboxylate, carboxamido, alkoxycarbonyl,aryloxycarbonyl, ammonium, aryl, heteroaryl, cycloalkyl, cycloalkenyl,heterocyclyl, polycyclyl, amino acid, peptide, saccharide, ribonucleicacid, (deoxy)ribonucleic acid, or a ligand for a G-protein-coupledreceptor;

d is an integer in the range 0 to 12 inclusive;

m is an integer in the range 0 to 6 inclusive;

n is an integer in the range 0 to 6 inclusive;

L is

X is —N(R²)—, —O—, or —S—;

R is selected from the group consisting of hydrogen, halogen, alkyl,alkenyl, alkynyl, hydroxyl, alkoxyl, acyl, acyloxy, acylamino, silyloxy,amino, nitro, sulfhydryl, alkylthio, imino, amido, phosphoryl,phosphonate, phosphine, carbonyl, carboxyl, carboxamide, anhydride,silyl, thioalkyl, alkylsulfonyl, arylsulfonyl, selenoalkyl, ketone,aldehyde, ester, heteroalkyl, cyano, guanidine, amidine, acetal, ketal,amine oxide, aryl, heteroaryl, aralkyl, heteroaralkyl, azido, aziridine,carbamoyl, epoxide, hydroxamic acid, imide, oxime, sulfonamide,thioamide, thiocarbamate, urea, thiourea, and —(CH₂)_(d)—R₈₀; and

R² is hydrogen or a lipophilic group.

In certain embodiments, the compounds of the present invention arerepresented by A and the attendant definitions, wherein said compound iscomplexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by A and the attendant definitions, wherein said compound iscomplexed with a radionuclide, wherein said radionuclide is technetiumor rhenium.

In another aspect, the present invention relates to a compound offormula B:

wherein, independently for each occurrence,

R¹ is H, alkyl, hydroxyalkyl, alkoxyalkyl, aminoalkyl, thioalkyl,alkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl, acyl,aminoacyl, hydroxyacyl, thioacyl, (amino)alkoxycarbonyl,(hydroxy)alkoxycarbonyl, (amino)alkylaminocarbonyl,(hydroxy)alkylaminocarbonyl, —CO₂H, —(CH₂)_(d)—R₈₀, or an amino acidradical;

R₈₀ is carboxaldehyde, carboxylate, carboxamido, alkoxycarbonyl,aryloxycarbonyl, ammonium, aryl, heteroaryl, cycloalkyl, cycloalkenyl,heterocyclyl, polycyclyl, amino acid, peptide, saccharide, ribonucleicacid, (deoxy)ribonucleic acid, or a ligand for a G-protein-coupledreceptor;

d is an integer in the range 0 to 12 inclusive;

m is an integer in the range 0 to 6 inclusive;

n is an integer in the range 0 to 6 inclusive;

R is selected from the group consisting of hydrogen, halogen, alkyl,alkenyl, alkynyl, hydroxyl, alkoxyl, acyl, acyloxy, acylamino, silyloxy,amino, nitro, sulfhydryl, alkylthio, imino, amido, phosphoryl,phosphonate, phosphine, carbonyl, carboxyl, carboxamide, anhydride,silyl, thioalkyl, alkylsulfonyl, arylsulfonyl, selenoalkyl, ketone,aldehyde, ester, heteroalkyl, cyano, guanidine, amidine, acetal, ketal,amine oxide, aryl, heteroaryl, aralkyl, heteroaralkyl, azido, aziridine,carbamoyl, epoxide, hydroxamic acid, imide, oxime, sulfonamide,thioamide, thiocarbamate, urea, thiourea, and —(CH₂)_(d)—R₈₀; and

R² is hydrogen or a lipophilic group.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein said compound iscomplexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein said compound iscomplexed with a radionuclide, wherein said radionuclide is technetiumor rhenium.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein m is 1.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein n is 1.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein m is 1; and n is1.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein R is hydrogen.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein R² is alipophilic group.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein R² is an ether,aralkyl or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein R is hydrogen;and R² is an ether, aralkyl or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein m is 1; n is 1;R is hydrogen; and R² is an ether, aralkyl or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein R¹ is—(CH₂)_(d)—R₈₀.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein m is 1; n is 1;R is hydrogen; R² is an ether, aralkyl or alkylaryl; and R¹ is—(CH₂)_(d)—R₈₀.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein m is 1; n is 1;R is hydrogen; R² is an ether, aralkyl or alkylaryl; and R¹ is—(CH₂)_(d)—R₈₀; wherein said compound is complexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein m is 1; n is 1;R is hydrogen; R² is an ether, aralkyl or alkylaryl; and R¹ is—(CH₂)_(d)—R₈₀; wherein said compound is complexed with a radionuclide,wherein said radionuclide is technetium or rhenium.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein R¹ is an aminoacid radical.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein R¹ is an aminoacid radical; m is 1; and n is 1.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein R¹ is an aminoacid radical; m is 1; n is 1; and R² is an ether, aralkyl or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein R¹ is an aminoacid radical; m is 1; n is 1; R is hydrogen; and R² is an ether, aralkylor alkylaryl; wherein said compound is complexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein R¹ is an aminoacid radical; m is 1; n is 1; R is hydrogen; and R² is an ether, aralkylor alkylaryl; wherein said compound is complexed with a radionuclide,wherein said radionuclide is technetium or rhenium.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein the amino acidradical is —CH₂CH₂CH₂CH₂CH(NH₂)CO₂H.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein the amino acidradical is —CH(CO₂H)CH₂CH₂CH₂CH₂NH₂.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein the amino acidradical is —CH₂CH₂CO₂H.

In certain embodiments, the compounds of the present invention arerepresented by B and the attendant definitions, wherein the amino acidradical is —CH(CO₂H)(CH₂)_(x)CH(NH₂)CO₂H, wherein x is an integer from 3to 9 inclusively.

In another aspect, the present invention relates to a compound offormula C:

wherein, independently for each occurrence,

Z is thioalkyl, carboxylate, 2-(carboxy)aryl, 2-(carboxy)heteroaryl,2-(hydroxy)aryl, 2-(hydroxy)heteroaryl, 2-(thiol)aryl, or2-(thiol)heteroaryl; and

R¹ is H, alkyl, hydroxyalkyl, alkoxyalkyl, aminoalkyl, thioalkyl,alkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl, acyl,aminoacyl, hydroxyacyl, thioacyl, (amino)alkoxycarbonyl,(hydroxy)alkoxycarbonyl, (amino)alkylaminocarbonyl,(hydroxy)alkylaminocarbonyl, —CO₂H, —(CH₂)_(d)—R₈₀, or an amino acidradical;

R₈₀ is carboxaldehyde, carboxylate, carboxamido, alkoxycarbonyl,aryloxycarbonyl, ammonium, aryl, heteroaryl, cycloalkyl, cycloalkenyl,heterocyclyl, polycyclyl, amino acid, peptide, saccharide, ribonucleicacid, (deoxy)ribonucleic acid, or a ligand for a G-protein-coupledreceptor;

d is an integer in the range 0 to 12 inclusive;

m is an integer in the range 0 to 6 inclusive;

n is an integer in the range 0 to 6 inclusive;

L is

X is —N(R²)—, —O—, or —S—;

R is selected from the group consisting of hydrogen, halogen, alkyl,alkenyl, alkynyl, hydroxyl, alkoxyl, acyl, acyloxy, acylamino, silyloxy,amino, nitro, sulfhydryl, alkylthio, imino, amido, phosphoryl,phosphonate, phosphine, carbonyl, carboxyl, carboxamide, anhydride,silyl, thioalkyl, alkylsulfonyl, arylsulfonyl, selenoalkyl, ketone,aldehyde, ester, heteroalkyl, cyano, guanidine, amidine, acetal, ketal,amine oxide, aryl, heteroaryl, aralkyl, heteroaralkyl, azido, aziridine,carbamoyl, epoxide, hydroxamic acid, imide, oxime, sulfonamide,thioamide, thiocarbamate, urea, thiourea, and —(CH₂)_(d)—R₈₀; and

R² is hydrogen or a lipophilic group.

In certain embodiments, the compounds of the present invention arerepresented by C and the attendant definitions, wherein said compound iscomplexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by C and the attendant definitions, wherein said compound iscomplexed with a radionuclide, wherein said radionuclide is technetiumor rhenium.

In another aspect, the present invention relates to a compound offormula D:

wherein, independently for each occurrence,

Z is thioalkyl, carboxylate, 2-(carboxy)aryl, 2-(carboxy)heteroaryl,2-(hydroxy)aryl, 2-(hydroxy)heteroaryl, 2-(thiol)aryl, or2-(thiol)heteroaryl; and

R¹ is H, alkyl, hydroxyalkyl, alkoxyalkyl, aminoalkyl, thioalkyl,alkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl, acyl,aminoacyl, hydroxyacyl, thioacyl, (amino)alkoxycarbonyl,(hydroxy)alkoxycarbonyl, (amino)alkylaminocarbonyl,(hydroxy)alkylaminocarbonyl, —CO₂H, —(CH₂)_(d)—R₈₀, or an amino acidradical;

R₈₀ is carboxaldehyde, carboxylate, carboxamido, alkoxycarbonyl,aryloxycarbonyl, ammonium, aryl, heteroaryl, cycloalkyl, cycloalkenyl,heterocyclyl, polycyclyl, amino acid, peptide, saccharide, ribonucleicacid, (deoxy)ribonucleic acid, or a ligand for a G-protein-coupledreceptor;

d is an integer in the range 0 to 12 inclusive;

m is an integer in the range 0 to 6 inclusive;

n is an integer in the range 0 to 6 inclusive; and

R is selected from the group consisting of hydrogen, halogen, alkyl,alkenyl, alkynyl, hydroxyl, alkoxyl, acyl, acyloxy, acylamino, silyloxy,amino, nitro, sulfhydryl, alkylthio, imino, amido, phosphoryl,phosphonate, phosphine, carbonyl, carboxyl, carboxamide, anhydride,silyl, thioalkyl, alkylsulfonyl, arylsulfonyl, selenoalkyl, ketone,aldehyde, ester, heteroalkyl, cyano, guanidine, amidine, acetal, ketal,amine oxide, aryl, heteroaryl, aralkyl, heteroaralkyl, azido, aziridine,carbamoyl, epoxide, hydroxamic acid, imide, oxime, sulfonamide,thioamide, thiocarbamate, urea, thiourea, and —(CH₂)_(d)—R₈₀.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein said compound iscomplexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein said compound iscomplexed with a radionuclide, wherein said radionuclide is technetiumor rhenium.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein Z iscarboxylate.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein m is 1.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein n is 1.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein m is 1; and n is1.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein Z iscarboxylate; m is 1; and n is 1.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein R is hydrogen.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein Z iscarboxylate; m is 1; n is 1; and R is hydrogen.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein R¹ is—(CH₂)_(d)—R₈₀.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein Z iscarboxylate; m is 1; n is 1; R is hydrogen; and R¹ is —(CH₂)_(d)—R₈₀.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein Z iscarboxylate; m is 1; n is 1; R is hydrogen; and R¹ is —(CH₂)_(d)—R₈₀;wherein said compound is complexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein Z iscarboxylate; m is 1; n is 1; R is hydrogen; and R¹ is —(CH₂)_(d)—R₈₀;wherein said compound is complexed with a radionuclide, wherein saidradionuclide is technetium or rhenium.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein R¹ is an aminoacid radical.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein R¹ is an aminoacid radical; m is 1; and n is 1.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein R¹ is an aminoacid radical; m is 1; n is 1; and R is hydrogen.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein R¹ is an aminoacid radical; m is 1; n is 1; and R is hydrogen; wherein said compoundis complexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein R¹ is an aminoacid radical; m is 1; n is 1; and R is hydrogen; wherein said compoundis complexed with a radionuclide, wherein said radionuclide istechnetium or rhenium.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein the amino acidradical is —CH₂CH₂CH₂CH₂CH(NH₂)CO₂H.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein the amino acidradical is —CH(CO₂H)CH₂CH₂CH₂CH₂NH₂.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein the amino acidradical is —CH₂CH₂CO₂H.

In certain embodiments, the compounds of the present invention arerepresented by D and the attendant definitions, wherein the amino acidradical is —CH(CO₂H)(CH₂)_(x)CH(NH₂)CO₂H, wherein x is an integer from 3to 9 inclusively.

In another aspect, the present invention relates to a compound offormula E:

wherein, independently for each occurrence,

m is an integer in the range 0 to 6 inclusive;

n is an integer in the range 0 to 6 inclusive;

p is an integer in the range of 1 to 10 inclusive;

Z is selected from the group consisting of —CH₂COOH, alkyl, aryl,aralkyl,

L is

X is —N(R²)—, —O—, or —S—;

R² is hydrogen or a lipophilic group;

R is halogen, alkyl, alkenyl, alkynyl, hydroxyl, alkoxyl, acyl, acyloxy,acylamino, silyloxy, amino, nitro, sulfhydryl, alkylthio, imino, amido,phosphoryl, phosphonate, phosphine, carbonyl, carboxyl, carboxamide,anhydride, silyl, thioalkyl, alkylsulfonyl, arylsulfonyl, selenoalkyl,ketone, aldehyde, ester, heteroalkyl, cyano, guanidine, amidine, acetal,ketal, amine oxide, aryl, heteroaryl, aralkyl, heteroaralkyl, azido,aziridine, carbamoyl, epoxide, hydroxamic acid, imide, oxime,sulfonamide, thioamide, thiocarbamate, urea, thiourea, and—(CH₂)_(d)—R₈₀;

R₈₀ is carboxaldehyde, carboxylate, carboxamido, alkoxycarbonyl,aryloxycarbonyl, ammonium, aryl, heteroaryl, cycloalkyl, cycloalkenyl,heterocyclyl, polycyclyl, amino acid, peptide, saccharide, ribonucleicacid, (deoxy)ribonucleic acid, or a ligand for a G-protein-coupledreceptor; and

d is an integer in the range 0 to 12 inclusive.

In certain embodiments, the compounds of the present invention arerepresented by E and the attendant definitions, wherein said compound iscomplexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by E and the attendant definitions, wherein said compound iscomplexed with a radionuclide, wherein said radionuclide is technetiumor rhenium.

In certain embodiments, the compounds of the present invention arerepresented by E and the attendant definitions, wherein L is

R is hydrogen; R² is hydrogen; and Z is alkyl.

In another aspect, the present invention relates to a compound offormula F:

wherein, independently for each occurrence,

L is

X is —N(R²)—, —O—, or —S—;

R is halogen, alkyl, alkenyl, alkynyl, hydroxyl, alkoxyl, acyl, acyloxy,acylamino, silyloxy, amino, nitro, sulfhydryl, alkylthio, imino, amido,phosphoryl, phosphonate, phosphine, carbonyl, carboxyl, carboxamide,anhydride, silyl, thioalkyl, alkylsulfonyl, arylsulfonyl, selenoalkyl,ketone, aldehyde, ester, heteroalkyl, cyano, guanidine, amidine, acetal,ketal, amine oxide, aryl, heteroaryl, aralkyl, heteroaralkyl, azido,aziridine, carbamoyl, epoxide, hydroxamic acid, imide, oxime,sulfonamide, thioamide, thiocarbamate, urea, thiourea, or—(CH₂)_(d)—R₈₀;

R₈₀ is carboxaldehyde, carboxylate, carboxamido, alkoxycarbonyl,aryloxycarbonyl, ammonium, aryl, heteroaryl, cycloalkyl, cycloalkenyl,heterocyclyl, polycyclyl, amino acid, peptide, saccharide, ribonucleicacid, (deoxy)ribonucleic acid, or ligand for a G-protein-coupledreceptor;

R₂ is H or a lipophilic group;

d is an integer in the range 0 to 12 inclusive;

m is an integer in the range 0 to 6 inclusive; and

n is an integer in the range 0 to 6 inclusive.

In certain embodiments, the compounds of the present invention arerepresented by F and the attendant definitions, wherein the compound iscomplexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by F and the attendant definitions, wherein the compound iscomplexed with a radionuclide, wherein the radionuclide is technetium orrhenium.

In another aspect, the present invention relates to a compound offormula G:

wherein, independently for each occurrence,

R is absent or present 1 or 2 times;

R is halogen, alkyl, alkenyl, alkynyl, hydroxyl, alkoxyl, acyl, acyloxy,acylamino, silyloxy, amino, nitro, sulfhydryl, alkylthio, imino, amido,phosphoryl, phosphonate, phosphine, carbonyl, carboxyl, carboxamide,anhydride, silyl, thioalkyl, alkylsulfonyl, arylsulfonyl, selenoalkyl,ketone, aldehyde, ester, heteroalkyl, cyano, guanidine, amidine, acetal,ketal, amine oxide, aryl, heteroaryl, aralkyl, heteroaralkyl, azido,aziridine, carbamoyl, epoxide, hydroxamic acid, imide, oxime,sulfonamide, thioamide, thiocarbamate, urea, thiourea, or—(CH₂)_(d)—R₈₀;

R₈₀ is carboxaldehyde, carboxylate, carboxamido, alkoxycarbonyl,aryloxycarbonyl, ammonium, aryl, heteroaryl, cycloalkyl, cycloalkenyl,heterocyclyl, polycyclyl, amino acid, peptide, saccharide, ribonucleicacid, (deoxy)ribonucleic acid, or ligand for a G-protein-coupledreceptor;

R₂ is H or a lipophilic group;

d is an integer in the range 0 to 12 inclusive;

m is an integer in the range 0 to 6 inclusive; and

n is an integer in the range 0 to 6 inclusive.

In certain embodiments, the compounds of the present invention arerepresented by G and the attendant definitions, wherein the compound iscomplexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by G and the attendant definitions, wherein the compound iscomplexed with a radionuclide, wherein the radionuclide is technetium orrhenium.

In certain embodiments, the compounds of the present invention arerepresented by G and the attendant definitions, wherein m is 1.

In certain embodiments, the compounds of the present invention arerepresented by G and the attendant definitions, wherein n is 1.

In certain embodiments, the compounds of the present invention arerepresented by G and the attendant definitions, wherein m is 1; and n is1.

In certain embodiments, the compounds of the present invention arerepresented by G and the attendant definitions, wherein R is absent.

In certain embodiments, the compounds of the present invention arerepresented by G and the attendant definitions, wherein R₂ is alipophilic group.

In certain embodiments, the compounds of the present invention arerepresented by G and the attendant definitions, wherein R₂ is an ether,aralkyl, or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by G and the attendant definitions, wherein R is absent; andR₂ is an ether, aralkyl, or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by G and the attendant definitions, wherein m is 1; n is 1;R is absent; and R₂ is an ether, aralkyl, or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by G and the attendant definitions, wherein m is 1; n is 1;R is absent; and R₂ is an ether, aralkyl, or alkylaryl; wherein thecompound is complexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by G and the attendant definitions, wherein m is 1; n is 1;R is absent; and R₂ is an ether, aralkyl, or alkylaryl; wherein thecompound is complexed with a radionuclide, wherein said radionuclide istechnetium or rhenium.

In another aspect, the present invention relates to a compound offormula II:

wherein, independently for each occurrence,

L is

X is —N(R²)—, —O—, or —S—;

R is halogen, alkyl, alkenyl, alkynyl, hydroxyl, alkoxyl, acyl, acyloxy,acylamino, silyloxy, amino, nitro, sulfhydryl, alkylthio, imino, amido,phosphoryl, phosphonate, phosphine, carbonyl, carboxyl, carboxamide,anhydride, silyl, thioalkyl, alkylsulfonyl, arylsulfonyl, selenoalkyl,ketone, aldehyde, ester, heteroalkyl, cyano, guanidine, amidine, acetal,ketal, amine oxide, aryl, heteroaryl, aralkyl, heteroaralkyl, azido,aziridine, carbamoyl, epoxide, hydroxamic acid, imide, oxime,sulfonamide, thioamide, thiocarbamate, urea, thiourea, or—(CH₂)_(d)—R₈₀;

R₈₀ is carboxaldehyde, carboxylate, carboxamido, alkoxycarbonyl,aryloxycarbonyl, ammonium, aryl, heteroaryl, cycloalkyl, cycloalkenyl,heterocyclyl, polycyclyl, amino acid, peptide, saccharide, ribonucleicacid, (deoxy)ribonucleic acid, or ligand for a G-protein-coupledreceptor;

R₂ is H or a lipophilic group;

R₃ represents a moiety comprising a neutral or anionic Lewis base, H,alkyl, hydroxyalkyl, alkoxyalkyl, aminoalkyl, thioalkyl, alkenyl,alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl, acyl, aminoacyl,hydroxyacyl, thioacyl, (amino)alkoxycarbonyl, (hydroxy)alkoxycarbonyl,(amino)alkylaminocarbonyl, (hydroxy)alkylaminocarbonyl, —CO₂H,—(CH₂)_(d)—R₈₀, or an amino acid radical;

d is an integer in the range 0 to 12 inclusive;

m is an integer in the range 0 to 6 inclusive; and

n is an integer in the range 0 to 6 inclusive.

In certain embodiments, the compounds of the present invention arerepresented by H and the attendant definitions, wherein the compound iscomplexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by H and the attendant definitions, wherein the compound iscomplexed with a radionuclide, wherein the radionuclide is technetium orrhenium.

In another aspect, the present invention relates to a compound offormula I:

wherein, independently for each occurrence,

R is absent or present 1 or 2 times;

R is halogen, alkyl, alkenyl, alkynyl, hydroxyl, alkoxyl, acyl, acyloxy,acylamino, silyloxy, amino, nitro, sulfhydryl, alkylthio, imino, amido,phosphoryl, phosphonate, phosphine, carbonyl, carboxyl, carboxamide,anhydride, silyl, thioalkyl, alkylsulfonyl, arylsulfonyl, selenoalkyl,ketone, aldehyde, ester, heteroalkyl, cyano, guanidine, amidine, acetal,ketal, amine oxide, aryl, heteroaryl, aralkyl, heteroaralkyl, azido,aziridine, carbamoyl, epoxide, hydroxamic acid, imide, oxime,sulfonamide, thioamide, thiocarbamate, urea, thiourea, or—(CH₂)_(d)—R₈₀;

R₈₀ is carboxaldehyde, carboxylate, carboxamido, alkoxycarbonyl,aryloxycarbonyl, ammonium, aryl, heteroaryl, cycloalkyl, cycloalkenyl,heterocyclyl, polycyclyl, amino acid, peptide, saccharide, ribonucleicacid, (deoxy)ribonucleic acid, or ligand for a G-protein-coupledreceptor;

R₂ is H or a lipophilic group;

R₃ is a moiety comprising a neutral or anionic Lewis base, H, alkyl,hydroxyalkyl, alkoxyalkyl, aminoalkyl, thioalkyl, alkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, acyl, aminoacyl, hydroxyacyl,thioacyl, (amino)alkoxycarbonyl, (hydroxy)alkoxycarbonyl,(amino)alkylaminocarbonyl, (hydroxy)alkylaminocarbonyl, —CO₂H,—(CH₂)_(d)—R₈₀, or an amino acid radical;

d is an integer in the range 0 to 12 inclusive;

m is an integer in the range 0 to 6 inclusive; and

n is an integer in the range 0 to 6 inclusive.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein the compound iscomplexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein the compound iscomplexed with a radionuclide, wherein the radionuclide is technetium orrhenium.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein m is 1.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein n is 1.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein m is 1; and n is1.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein R is absent.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein R₂ is alipophilic group.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein R₂ is an ether,aralkyl, or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein R₃ is a moietycomprising an anionic Lewis base.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein R₃ is acarboxylate, thiolate, or phenolate.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein R is absent; andR₂ is an ether, aralkyl, or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein R is absent; R₂is an ether, aralkyl, or alkylaryl; and R₃ is a carboxylate, thiolate,or phenolate.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein m is 1; n is 1;R is absent; and R₂ is an ether, aralkyl, or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein m is 1; n is 1;R is absent; R₂ is an ether, aralkyl, or alkylaryl; and R₃ is acarboxylate, thiolate, or phenolate.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein m is 1; n is 1;R is absent; and R₂ is an ether, aralkyl, or alkylaryl; wherein saidcompound is complexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein m is 1; n is 1;R is absent; R₂ is an ether, aralkyl, or alkylaryl; and R₃ is acarboxylate, thiolate, or phenolate; wherein the compound is complexedwith a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein m is 1; n is 1;R is absent; and R₂ is an ether, aralkyl, or alkylaryl; wherein thecompound is complexed with a radionuclide, wherein the radionuclide istechnetium or rhenium.

In certain embodiments, the compounds of the present invention arerepresented by I and the attendant definitions, wherein m is 1; n is 1;R is absent; R₂ is an ether, aralkyl, or alkylaryl; and R₃ is acarboxylate, thiolate, or phenolate; wherein the compound is complexedwith a radionuclide, wherein the radionuclide is technetium or rhenium.

In another aspect, the present invention relates to a compound offormula J:

wherein, independently for each occurrence,

n is an integer in the range 0 to 6 inclusive;

m is an integer in the range 0 to 6 inclusive;

L is

X is —N(R²)—, —O—, or —S—;

R₁ is H, alkyl, hydroxyalkyl, alkoxyalkyl, aminoalkyl, thioalkyl,alkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl, acyl,aminoacyl, hydroxyacyl, thioacyl, (amino)alkoxycarbonyl,(hydroxy)alkoxycarbonyl, (amino)alkylaminocarbonyl,(hydroxy)alkylaminocarbonyl, —CO₂H, —(CH₂)_(d)—R₈₀, or an amino acidradical;

R₃ is a moiety comprising a neutral or anionic Lewis base, H, alkyl,hydroxyalkyl, alkoxyalkyl, aminoalkyl, thioalkyl, alkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, acyl, aminoacyl, hydroxyacyl,thioacyl, (amino)alkoxycarbonyl, (hydroxy)alkoxycarbonyl,(amino)alkylaminocarbonyl, (hydroxy)alkylaminocarbonyl, —CO₂H,—(CH₂)_(d)—R₈₀, or an amino acid radical; and

R₈₀ represents independently for each occurrence carboxaldehyde,carboxylate, carboxamido, alkoxycarbonyl, aryloxycarbonyl, ammonium,aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocyclyl, polycyclyl,amino acid, peptide, saccharide, ribonucleic acid, (deoxy)ribonucleicacid, or ligand for a G-protein-coupled receptor.

In certain embodiments, the compounds of the present invention arerepresented by J and the attendant definitions, wherein the compound iscomplexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by J and the attendant definitions, wherein the compound iscomplexed with a radionuclide, wherein the radionuclide is technetium orrhenium.

In another aspect, the present invention relates to a compound offormula K:

wherein, independently for each occurrence,

R is absent or present 1 or 2 times;

R is halogen, alkyl, alkenyl, alkynyl, hydroxyl, alkoxyl, acyl, acyloxy,acylamino, silyloxy, amino, nitro, sulfhydryl, alkylthio, imino, amido,phosphoryl, phosphonate, phosphine, carbonyl, carboxyl, carboxamide,anhydride, silyl, thioalkyl, alkylsulfonyl, arylsulfonyl, selenoalkyl,ketone, aldehyde, ester, heteroalkyl, cyano, guanidine, amidine, acetal,ketal, amine oxide, aryl, heteroaryl, aralkyl, heteroaralkyl, azido,aziridine, carbamoyl, epoxide, hydroxamic acid, imide, oxime,sulfonamide, thioamide, thiocarbamate, urea, thiourea, or—(CH₂)_(d)—R₈₀;

R₈₀ is carboxaldehyde, carboxylate, carboxamido, alkoxycarbonyl,aryloxycarbonyl, ammonium, aryl, heteroaryl, cycloalkyl, cycloalkenyl,heterocyclyl, polycyclyl, amino acid, peptide, saccharide, ribonucleicacid, (deoxy)ribonucleic acid, or ligand for a G-protein-coupledreceptor;

R₁ is H, alkyl, hydroxyalkyl, alkoxyalkyl, aminoalkyl, thioalkyl,alkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl, acyl,aminoacyl, hydroxyacyl, thioacyl, (amino)alkoxycarbonyl,(hydroxy)alkoxycarbonyl, (amino)alkylaminocarbonyl,(hydroxy)alkylaminocarbonyl, —CO₂H, —(CH₂)_(d)—R₈₀, or an amino acidradical;

R₂ is H or a lipophilic group;

R₃ is a moiety comprising a neutral or anionic Lewis base, H, alkyl,hydroxyalkyl, alkoxyalkyl, aminoalkyl, thioalkyl, alkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, acyl, aminoacyl, hydroxyacyl,thioacyl, (amino)alkoxycarbonyl, (hydroxy)alkoxycarbonyl,(amino)alkylaminocarbonyl, (hydroxy)alkylaminocarbonyl, —CO₂H,—(CH₂)_(d)—R₈₀, or an amino acid radical;

d is an integer in the range 0 to 12 inclusive;

m is an integer in the range 0 to 6 inclusive; and

n is an integer in the range 0 to 6 inclusive.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein the compound iscomplexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein the compound iscomplexed with a radionuclide, wherein the radionuclide is technetium orrhenium.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein m is 1.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein n is 1.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein m is 1; and n is1.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R is absent.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₂ is alipophilic group.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₂ is an ether,aralkyl, or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₃ is a moietycomprising an anionic Lewis base.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₃ is acarboxylate, thiolate, or phenolate.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R is absent; andR₂ is an ether, aralkyl, or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R is absent; R₂is an ether, aralkyl, or alkylaryl; and R₃ is a carboxylate, thiolate,or phenolate.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein m is 1; n is 1;R is absent; and R₂ is an ether, aralkyl, or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein m is 1; n is 1;R is absent; R₂ is an ether, aralkyl, or alkylaryl; and R₃ is acarboxylate, thiolate, or phenolate.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₁ is—(CH₂)_(d)—R₈₀.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein m is 1; n is 1;R is absent; R₂ is an ether, aralkyl, or alkylaryl; and R₁ is—(CH₂)_(d)—R₈₀.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein m is 1; n is 1;R is absent; R₂ is an ether, aralkyl, or alkylaryl; R₃ is a carboxylate,thiolate, or phenolate; and R₁ is —(CH₂)_(d)—R₈₀.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein m is 1; n is 1;R is absent; R₂ is an ether, aralkyl, or alkylaryl; and R₁ is—(CH₂)_(d)—R₈₀; wherein the compound is complexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein m is 1; n is 1;R is absent; R₂ is an ether, aralkyl, or alkylaryl; R₃ is a carboxylate,thiolate, or phenolate; and R₁ is —(CH₂)_(d)—R₈₀; wherein the compoundis complexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein m is 1; n is 1;R is absent; R₂ is an ether, aralkyl, or alkylaryl; and R₁ is—(CH₂)_(d)—R₈₀; wherein the compound is complexed with a radionuclide,wherein the radionuclide is technetium or rhenium.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein m is 1; n is 1;R is absent; R₂ is an ether, aralkyl, or alkylaryl; R₃ is a carboxylate,thiolate, or phenolate; and R₁ is —(CH₂)_(d)—R₈₀; wherein the compoundis complexed with a radionuclide, wherein the radionuclide is technetiumor rhenium.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₁ is an aminoacid radical.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₁ is an aminoacid radical; m is 1; and n is 1.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₁ is an aminoacid radical; m is 1; n is 1; R is absent; and R₂ is an ether, aralkyl,or alkylaryl.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₁ is an aminoacid radical; m is 1; n is 1; R is absent; R₂ is an ether, aralkyl, oralkylaryl; and R₃ is a carboxylate, thiolate, or phenolate.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₁ is an aminoacid radical; m is 1; n is 1; R is absent; and R₂ is an ether, aralkyl,or alkylaryl; wherein the compound is complexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₁ is an aminoacid radical; m is 1; n is 1; R is absent; R₂ is an ether, aralkyl, oralkylaryl; and R₃ is a carboxylate, thiolate, or phenolate; wherein thecompound is complexed with a radionuclide.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₁ is an aminoacid radical; m is 1; n is 1; R is absent; and R₂ is an ether, aralkyl,or alkylaryl; wherein the compound is complexed with a radionuclide,wherein the radionuclide is technetium or rhenium.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein R₁ is an aminoacid radical; m is 1; n is 1; R is absent; R₂ is an ether, aralkyl, oralkylaryl; and R₃ is a carboxylate, thiolate, or phenolate; wherein thecompound is complexed with a radionuclide, wherein the radionuclide istechnetium or rhenium.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein the amino acidradical is —CH₂CH₂CH₂CH₂CH(NH₂)CO₂H.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein the amino acidradical is —CH(CO₂H)CH₂CH₂CH₂CH₂NH₂.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein the amino acidradical is —CH₂CH₂CO₂H.

In certain embodiments, the compounds of the present invention arerepresented by K and the attendant definitions, wherein the amino acidradical is —CH(CO₂H)(CH₂)_(x)CH(NH₂)CO₂H, wherein x is an integer from 3to 9 inclusively.

In certain embodiments, the present invention relates to a formulation,comprising a compound represented by A to K and the attendantdefinitions; and a pharmaceutically acceptable excipient.

In certain embodiments, the present invention relates to a method ofimaging a region in a patient, comprising administering to the patient adiagnostically effective amount of a compound represented by A to K,wherein the compound is complexed with a radionuclide.

In certain embodiments, the present invention relates to a method ofimaging a region in a patient, wherein said region of said patient isthe head or thorax, comprising administering to the patient adiagnostically effective amount of a compound represented by A to K,wherein the compound is complexed with a radionuclide.

In certain embodiments, the present invention relates to a method ofpreparing a peptide conjugate incorporating a compound of claimrepresented by A to K, wherein the peptide conjugate is prepared usingsolid phase synthetic techniques.

The novel ligands described above, may be incorporated into radionuclidecomplexes used as radiographic imaging agents. Further, these ligands orcomplexes can be covalently or non-covalently attached to biologicallyactive carrier molecules, such as, antibodies, enzymes, peptidespeptidomimetics, hormones, and the like. The complexes of the presentinvention are prepared by reacting one of the aforementioned ligandswith a radionuclide containing solution under radionuclide complexforming reaction conditions. In particular, if a technetium agent isdesired, the reaction is carried out with a pertechnetate solution undertechnetium-99m complex forming reaction conditions. The solvent may thenbe removed by any appropriate means, such as evaporation. The complexesare then prepared for administration to the patient by dissolution orsuspension in a pharmaceutically acceptable vehicle.

The present invention also relates to imaging agents containing aradionuclide complex as described above, in an amount sufficient forimaging, together with a pharmaceutically acceptable radiologicalvehicle. The radiological vehicle should be suitable for injection oraspiration, such as human serum albumin; aqueous buffer solutions, e.g.,tris(hydromethyl)aminomethane (and its salts), phosphate, citrate,bicarbonate, etc; sterile water; physiological saline; and balancedionic solutions containing chloride and or dicarbonate salts or normalblood plasma cations such as calcium, potassium, sodium, and magnesium.

The concentration of the imaging agent according to the presentinvention in the radiological vehicle should be sufficient to providesatisfactory imaging, for example, when using an aqueous solution, thedosage is about 1.0 to 50 millicuries. The imaging agent should beadministered so as to remain in the patient for about 1 to 3 hours,although both longer and shorter time periods are acceptable. Therefore,convenient ampules containing 1 to 10 mL of aqueous solution may beprepared.

Imaging may be carried out in the normal manner, for example byinjecting a sufficient amount of the imaging composition to provideadequate imaging and then scanning with a suitable machine, such as agamma camera. In certain embodiments, the present invention relates to amethod of imaging a region in a patient, comprising the steps of:administering to a patient a diagnostically effective amount of acompound of the present invention complexed with a radionuclide;exposing a region of said patient to radiation; and obtaining an imageof said region of said patient. In certain embodiments of the method ofimaging a region in a patient, said region of said patient is the heador thorax.

8. Pharmaceutical Formulations

In another aspect, the present invention provides pharmaceuticallyacceptable compositions which comprise a therapeutically-effectiveamount of one or more of the compounds described above, formulatedtogether with one or more pharmaceutically acceptable carriers(additives) and/or diluents. As described in detail below, thepharmaceutical compositions of the present invention may be speciallyformulated for administration in solid or liquid form, including thoseadapted for the following: (1) oral administration, for example,drenches (aqueous or non-aqueous solutions or suspensions), tablets,e.g., those targeted for buccal, sublingual, and systemic absorption,boluses, powders, granules, pastes for application to the tongue; (2)parenteral administration, for example, by subcutaneous, intramuscular,intravenous or epidural injection as, for example, a sterile solution orsuspension, or sustained-release formulation; (3) topical application,for example, as a cream, ointment, or a controlled-release patch orspray applied to the skin; (4) intravaginally or intrarectally, forexample, as a pessary, cream or foam; (5) sublingually; (6) ocularly;(7) transdermally; or (8) nasally.

The phrase “therapeutically-effective amount” as used herein means thatamount of a compound, material, or composition comprising a compound ofthe present invention which is effective for producing some desiredtherapeutic effect in at least a sub-population of cells in an animal ata reasonable benefit/risk ratio applicable to any medical treatment.

The phrase “pharmaceutically acceptable” is employed herein to refer tothose compounds, materials, compositions, and/or dosage forms which are,within the scope of sound medical judgment, suitable for use in contactwith the tissues of human beings and animals without excessive toxicity,irritation, allergic response, or other problem or complication,commensurate with a reasonable benefit/risk ratio.

The phrase “pharmaceutically-acceptable carrier” as used herein means apharmaceutically-acceptable material, composition or vehicle, such as aliquid or solid filler, diluent, excipient, or solvent encapsulatingmaterial, involved in carrying or transporting the subject compound fromone organ, or portion of the body, to another organ, or portion of thebody. Each carrier must be “acceptable” in the sense of being compatiblewith the other ingredients of the formulation and not injurious to thepatient. Some examples of materials which can serve aspharmaceutically-acceptable carriers include: (1) sugars, such aslactose, glucose and sucrose; (2) starches, such as corn starch andpotato starch; (3) cellulose, and its derivatives, such as sodiumcarboxymethyl cellulose, ethyl cellulose and cellulose acetate; (4)powdered tragacanth; (5) malt; (6) gelatin; (7) talc; (8) excipients,such as cocoa butter and suppository waxes; (9) oils, such as peanutoil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil andsoybean oil; (10) glycols, such as propylene glycol; (11) polyols, suchas glycerin, sorbitol, mannitol and polyethylene glycol; (12) esters,such as ethyl oleate and ethyl laurate; (13) agar; (14) bufferingagents, such as magnesium hydroxide and aluminum hydroxide; (15) alginicacid; (16) pyrogen-free water; (17) isotonic saline; (18) Ringer'ssolution; (19) ethyl alcohol; (20) pH buffered solutions; (21)polyesters, polycarbonates and/or polyanhydrides; and (22) othernon-toxic compatible substances employed in pharmaceutical formulations.

Formulations of the present invention may be based in part on liposomes.Liposomes consist of a phospholipid bilayer which forms a shell aroundan aqueous core. Methods for preparing liposomes for administration to apatient are known to those skilled in the art; for example, U.S. Pat.No. 4,798,734 describes methods for encapsulation of biologicalmaterials in liposomes. The biological material is dissolved in aaqueous solution, and the appropriate phospholipids and lipids areadded, along with surfactants if required. The material is then dialyzedor sonicated, as necessary. A review of known methods is presented by G.Gregoriadis, Chapter 14 (“Liposomes”), in Drug Carriers in Biology andMedicine, pp. 287-341 (Academic Press, 1979).

Formulations of the present invention may be based in part on polymericmicroparticles. Microspheres formed of polymers or proteins are alsowell known to those skilled in the art, and can be tailored for passagethrough the gastrointestinal tract, as described in U.S. Pat. Nos.4,906,474, 4,925,673, and 3,625,214, for example. There are a number ofwell-known methods, including solvent evaporation and coacervation/phaseseparation, for preparing microspheres. Bioerodible microspheres can beprepared using any of the methods developed for making microspheres fordrug delivery, as described, for example, by Mathiowitz et al., J. Appl.Polymer Sci. 35, 755-774(1988), and P. Deasy, in Microencapsulation andRelated Drug Processes, pp. 61-193, (Dekker, 1984), the teachings ofwhich are incorporated herein. The selection of a method depends on thedrug properties and choice of polymer, as well as the size, externalmorphology, and degree of crystallinity desired, as discussed, forexample, by Benita et al., J. Pharm. Sci. 73, 1721-1724 (1984), Jaliland Nixon, J. Microencapsulation, 7, 297-325(1990), and Mathiowitz etal., Scanning Microscopy 4, 329-340(1990), the teachings of which areincorporated herein.

In solvent evaporation, described, for example, in Mathiowitz et al.,(1990), Benita, and U.S. Pat. No. 4,272,398 to Jaffe, the polymer isdissolved in a volatile organic solvent. The drug, either in soluble orparticulate form, is added to the polymer solution and the mixture issuspended in an aqueous phase containing a surface active agent such aspoly(vinyl alcohol). The resulting emulsion is stirred until most of theorganic solvent evaporates, leaving solid microspheres. Microspheres ofvarious sizes (1-1000 microns) and morphologies may be obtained by thismethod, which is useful for non-labile polymers.

Coacervation/phase separation techniques have been used to encapsulateboth solid and liquid core materials with various polymer coatings. U.S.Pat. Nos. 2,730,456, 2,730,457, and 2,800,457 to Green and Schleichter,describe gelatin and gelatin-acacia (gum arabic) coating systems, forexample. Simple coacervation employs a single colloid (e.g. gelatin inwater) and involves the removal of the associated water from around thedispersed colloid by agents with a higher affinity for water, such asalcohols and salts. Complex coacervation employs more than one colloid,and the separation proceeds mainly by charge neutralization of thecolloids carrying opposite charges rather than by dehydration.Coacervation may also be induced using nonaqueous vehicles, as describedin Nakano et al., Int. J. Pharm, 4, 29-298(1980), for example.

Hydrogel microspheres made of gel-type polymers such as alginate orpolyphosphazenes or other dicarboxylic polymers can be prepared bydissolving the polymer in an aqueous solution, suspending the materialto be incorporated into the mixture, and extruding the polymer mixturethrough a microdroplet forming device, equipped with a nitrogen gas jet.The resulting microspheres fall into a slowly stirring, ionic hardeningbath, as illustrated, for example, by Salib, et al., PharmazeutischeIndustrie 40-11A, 1230(1978), the teachings of which are incorporatedherein. The advantage of this system is the ability to further modifythe surface of the microspheres by coating them with polycationicpolymers (such as polylysine) after fabrication, as described, forexample, by Lim et al, J. Pharm Sci. 70, 351-354(1981). The microsphereparticle size depends upon the extruder size as well as the polymer andgas flow rates.

Examples of polymers that can be used include polyamides,polycarbonates, polyalkylenes and derivatives thereof including,polyalkylene glycols, polyalkylene oxides, polyalkylene terepthalates,polymers of acrylic and methacrylic esters, including poly(methylmethacrylate), poly(ethyl methacrylate), poly(butylmethacrylate),poly(isobutyl methacrylate), poly(hexylmethacrylate), poly(isodecylmethacrylate), poly(lauryl methacrylate), poly(phenyl methacrylate),poly(methyl acrylate), poly(isopropyl acrylate), poly(isobutylacrylate), and poly(octadecyl acrylate), polyvinyl polymers includingpolyvinyl alcohols, polyvinyl ethers, polyvinyl esters, polyvinylhalides, poly(vinyl acetate), and polyvinylpyrrolidone, polyglycolides,polysiloxanes, polyurethanes and co-polymers thereof, cellulosesincluding alkyl cellulose, hydroxyalkyl celluloses, cellulose ethers,cellulose esters, nitro celluloses, methyl cellulose, ethyl cellulose,hydroxypropyl cellulose, hydroxy-propyl methyl cellulose, hydroxybutylmethyl cellulose, cellulose acetate, cellulose propionate, celluloseacetate butyrate, cellulose acetate phthalate, carboxylethyl cellulose,cellulose triacetate, and cellulose sulphate sodium salt, polypropylene,polyethylenes including poly(ethylene glycol), poly(ethylene oxide), andpoly(ethylene terephthalate), and polystyrene.

Examples of biodegradable polymers include synthetic polymers such aspolymers of lactic acid and glycolic acid, polyanhydrides,poly(ortho)esters, polymethanes, poly(butic acid), poly(valeric acid),and poly(lactide-cocaprolactone), and natural polymers such as alginateand other polysaccharides including dextran and cellulose, collagen,chemical derivatives thereof (substitutions, additions of chemicalgroups, for example, alkyl, alkylene, hydroxylations, oxidations, andother modifications routinely made by those skilled in the art), albuminand other hydrophilic proteins, zein and other prolamines andhydrophobic proteins, copolymers and mixtures thereof. In general, thesematerials degrade either by enzymatic hydrolysis or exposure to water invivo, by surface or bulk erosion.

Bioadhesive polymers of particular interest include bioerodiblehydrogels described by H. S. Sawhney, C. P. Pathak and J. A. Hubbell inMacromolecules, 1993, 26, 581-587, the teachings of which areincorporated herein, polyhyaluronic acids, casein, gelatin, glutin,polyanhydrides, polyacrylic acid, alginate, chitosan, poly(methylmethacrylates), poly(ethyl methacrylates), poly(butylmethacrylate),poly(isobutyl methacrylate), poly(hexylmethacrylate), poly(isodecylmethacrylate), poly(lauryl methacrylate), poly(phenyl methacrylate),poly(methyl acrylate), poly(isopropyl acrylate), poly(isobutylacrylate), and poly(octadecyl acrylate).

A diluent used in a composition of the present invention can be one ormore compounds which are capable of densifying the active principle togive the desired mass. The preferred diluents are mineral phosphatessuch as calcium phosphates; sugars such as hydrated or anhydrouslactose, or mannitol; and cellulose or cellulose derivatives, forexample microcrystalline cellulose, starch, corn starch orpregelatinized starch. Very particularly preferred diluents are lactosemonohydrate, mannitol, microcrystalline cellulose and corn starch, usedby themselves or in a mixture, for example a mixture of lactosemonohydrate and corn starch or a mixture of lactose monohydrate, cornstarch and microcrystalline cellulose.

A binder employed in a composition of the present invention can be oneor more compounds which are capable of densifying a compound of formula(I), converting it to coarser and denser particles with better flowproperties. The preferred binders are alginic acid or sodium alginate;cellulose and cellulose derivatives such as sodium carboxymethylcellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropylcellulose, hydroxypropyl methyl cellulose or methyl cellulose, gelatin;acrylic acid polymers; and povidone, for example povidone K-30;hydroxypropyl methyl cellulose and povidone K-30 are very particularlypreferred binders.

A disintegrating agent employed in a composition of the presentinvention can be one or more compounds which facilitate thedisintegration of the prepared formulation when it is placed in anaqueous medium. The preferred disintegrating agents are cellulose orcellulose derivatives such as sodium carboxymethyl cellulose,crosslinked sodium carboxymethyl cellulose, micro-crystalline cellulose,cellulose powder, crospovidone; pregelatinized starch, sodium starchglyconate, sodium carboxymethyl starch, or starch. Crospovidone,crosslinked sodium carboxymethyl cellulose and sodium carboxymethylstarch are preferred disintegrating agents.

An antiadhesive employed in a composition of the present invention canbe one or more compounds which are capable of reducing the stickycharacter of the formulation, for example of preventing adhesion tometal surfaces. The preferred antiadhesives are compounds containingsilicon, for example silica or talcum.

A flow promoter employed in a composition of the present invention canbe one or more compounds which are capable of facilitating the flow ofthe prepared formulation. The preferred flow promoters are compoundscontaining silicon, for example anhydrous colloidal silica orprecipitated silica.

A lubricant employed in a composition of the present invention can beone or more compounds which are capable of preventing the problemsassociated with the preparation of dry forms, such as the stickingand/or seizing problems which occur in the machines during compressionor filling. The preferred lubricants are fatty acids or fatty acidderivatives such as calcium stearate, glyceryl monostearate, glycerylpalmitostearate, magnesium stearate, sodium laurylsulfate, sodiumstearylfumarate, zinc stearate or stearic acid; hydrogenated vegetableoils, for example hydrogenated castor oil; polyalkylene glycols orpolyethylene glycol; sodium benzoate; or talcum. Magnesium stearate orsodium stearylfumarate is preferred according to the present invention.

A color employed in a formulation of the present invention can be one ormore compounds which are capable of imparting the desired color to theprepared formulation. The addition of a color can serve for example todifferentiate between formulations containing different doses of activeprinciple. The preferred colors are iron oxides.

As set out above, certain embodiments of the present compounds maycontain a basic functional group, such as amino or alkylamino, and are,thus, capable of forming pharmaceutically-acceptable salts withpharmaceutically-acceptable acids. The term “pharmaceutically-acceptablesalts” in this respect, refers to the relatively non-toxic, inorganicand organic acid addition salts of compounds of the present invention.These salts can be prepared in situ in the administration vehicle or thedosage form manufacturing process, or by separately reacting a purifiedcompound of the invention in its free base form with a suitable organicor inorganic acid, and isolating the salt thus formed during subsequentpurification. Representative salts include the hydrobromide,hydrochloride, sulfate, bisulfate, phosphate, nitrate, acetate,valerate, oleate, palmitate, stearate, laurate, benzoate, lactate,phosphate, tosylate, citrate, maleate, fumarate, succinate, tartrate,napthylate, mesylate, glucoheptonate, lactobionate, and laurylsulphonatesalts and the like. (See, for example, Berge et al. (1977)“Pharmaceutical Salts”, J. Pharm. Sci. 66:1-19)

The pharmaceutically acceptable salts of the subject compounds includethe conventional nontoxic salts or quaternary ammonium salts of thecompounds, e.g., from non-toxic organic or inorganic acids. For example,such conventional nontoxic salts include those derived from inorganicacids such as hydrochloride, hydrobromic, sulfuric, sulfamic,phosphoric, nitric, and the like; and the salts prepared from organicacids such as acetic, propionic, succinic, glycolic, stearic, lactic,malic, tartaric, citric, ascorbic, palmitic, maleic, hydroxymaleic,phenylacetic, glutamic, benzoic, salicyclic, sulfanilic,2-acetoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethanedisulfonic, oxalic, isothionic, and the like.

In other cases, the compounds of the present invention may contain oneor more acidic functional groups and, thus, are capable of formingpharmaceutically-acceptable salts with pharmaceutically-acceptablebases. The term “pharmaceutically-acceptable salts” in these instancesrefers to the relatively non-toxic, inorganic and organic base additionsalts of compounds of the present invention. These salts can likewise beprepared in situ in the administration vehicle or the dosage formmanufacturing process, or by separately reacting the purified compoundin its free acid form with a suitable base, such as the hydroxide,carbonate or bicarbonate of a pharmaceutically-acceptable metal cation,with ammonia, or with a pharmaceutically-acceptable organic primary,secondary or tertiary amine. Representative alkali or alkaline earthsalts include the lithium, sodium, potassium, calcium, magnesium, andaluminum salts and the like. Representative organic amines useful forthe formation of base addition salts include ethylamine, diethylamine,ethylenediamine, ethanolamine, diethanolamine, piperazine and the like.(See, for example, Berge et al., supra)

Wetting agents, emulsifiers and lubricants, such as sodium laurylsulfate and magnesium stearate, as well as coloring agents, releaseagents, coating agents, sweetening, flavoring and perfuming agents,preservatives and antioxidants can also be present in the compositions.

Examples of pharmaceutically-acceptable antioxidants include: (1) watersoluble antioxidants, such as ascorbic acid, cysteine hydrochloride,sodium bisulfate, sodium metabisulfite, sodium sulfite and the like; (2)oil-soluble antioxidants, such as ascorbyl palmitate, butylatedhydroxyanisole (BHA), butylated hydroxytoluene (BHT), lecithin, propylgallate, alpha-tocopherol, and the like; and (3) metal chelating agents,such as citric acid, ethylenediamine tetraacetic acid (EDTA), sorbitol,tartaric acid, phosphoric acid, and the like.

Formulations of the present invention include those suitable for oral,nasal, topical (including buccal and sublingual), rectal, vaginal and/orparenteral administration. The formulations may conveniently bepresented in unit dosage form and may be prepared by any methods wellknown in the art of pharmacy. The amount of active ingredient which canbe combined with a carrier material to produce a single dosage form willvary depending upon the host being treated, the particular mode ofadministration. The amount of active ingredient which can be combinedwith a carrier material to produce a single dosage form will generallybe that amount of the compound which produces a therapeutic effect.Generally, out of one hundred percent, this amount will range from about1 percent to about ninety-nine percent of active ingredient, preferablyfrom about 5 percent to about 70 percent, most preferably from about 10percent to about 30 percent.

In certain embodiments, a formulation of the present invention comprisesan excipient selected from the group consisting of cyclodextrins,liposomes, micelle forming agents, e.g., bile acids, and polymericcarriers, e.g., polyesters and polyanhydrides; and a compound of thepresent invention. In certain embodiments, an aforementioned formulationrenders orally bioavailable a compound of the present invention.

Methods of preparing these formulations or compositions include the stepof bringing into association a compound of the present invention withthe carrier and, optionally, one or more accessory ingredients. Ingeneral, the formulations are prepared by uniformly and intimatelybringing into association a compound of the present invention withliquid carriers, or finely divided solid carriers, or both, and then, ifnecessary, shaping the product.

Formulations of the invention suitable for oral administration may be inthe form of capsules, cachets, pills, tablets, lozenges (using aflavored basis, usually sucrose and acacia or tragacanth), powders,granules, or as a solution or a suspension in an aqueous or non-aqueousliquid, or as an oil-in-water or water-in-oil liquid emulsion, or as anelixir or syrup, or as pastilles (using an inert base, such as gelatinand glycerin, or sucrose and acacia) and/or as mouth washes and thelike, each containing a predetermined amount of a compound of thepresent invention as an active ingredient. A compound of the presentinvention may also be administered as a bolus, electuary or paste.

In solid dosage forms of the invention for oral administration(capsules, tablets, pills, dragees, powders, granules and the like), theactive ingredient is mixed with one or more pharmaceutically-acceptablecarriers, such as sodium citrate or dicalcium phosphate, and/or any ofthe following: (1) fillers or extenders, such as starches, lactose,sucrose, glucose, mannitol, and/or silicic acid; (2) binders, such as,for example, carboxymethylcellulose, alginates, gelatin, polyvinylpyrrolidone, sucrose and/or acacia; (3) humectants, such as glycerol;(4) disintegrating agents, such as agar-agar, calcium carbonate, potatoor tapioca starch, alginic acid, certain silicates, and sodiumcarbonate; (5) solution retarding agents, such as paraffin; (6)absorption accelerators, such as quaternary ammonium compounds; (7)wetting agents, such as, for example, cetyl alcohol, glycerolmonostearate, and non-ionic surfactants; (8) absorbents, such as kaolinand bentonite clay; (9) lubricants, such a talc, calcium stearate,magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate,and mixtures thereof; and (10) coloring agents. In the case of capsules,tablets and pills, the pharmaceutical compositions may also comprisebuffering agents. Solid compositions of a similar type may also beemployed as fillers in soft and hard-shelled gelatin capsules using suchexcipients as lactose or milk sugars, as well as high molecular weightpolyethylene glycols and the like.

A tablet may be made by compression or molding, optionally with one ormore accessory ingredients. Compressed tablets may be prepared usingbinder (for example, gelatin or hydroxypropylmethyl cellulose),lubricant, inert diluent, preservative, disintegrant (for example,sodium starch glycolate or cross-linked sodium carboxymethyl cellulose),surface-active or dispersing agent. Molded tablets may be made bymolding in a suitable machine a mixture of the powdered compoundmoistened with an inert liquid diluent.

The tablets, and other solid dosage forms of the pharmaceuticalcompositions of the present invention, such as dragees, capsules, pillsand granules, may optionally be scored or prepared with coatings andshells, such as enteric coatings and other coatings well known in thepharmaceutical-formulating art. They may also be formulated so as toprovide slow or controlled release of the active ingredient thereinusing, for example, hydroxypropylmethyl cellulose in varying proportionsto provide the desired release profile, other polymer matrices,liposomes and/or microspheres. They may be formulated for rapid release,e.g., freeze-dried. They may be sterilized by, for example, filtrationthrough a bacteria-retaining filter, or by incorporating sterilizingagents in the form of sterile solid compositions which can be dissolvedin sterile water, or some other sterile injectable medium immediatelybefore use. These compositions may also optionally contain opacifyingagents and may be of a composition that they release the activeingredient(s) only, or preferentially, in a certain portion of thegastrointestinal tract, optionally, in a delayed manner. Examples ofembedding compositions which can be used include polymeric substancesand waxes. The active ingredient can also be in micro-encapsulated form,if appropriate, with one or more of the above-described excipients.

Liquid dosage forms for oral administration of the compounds of theinvention include pharmaceutically acceptable emulsions, microemulsions,solutions, suspensions, syrups and elixirs. In addition to the activeingredient, the liquid dosage forms may contain inert diluents commonlyused in the art, such as, for example, water or other solvents,solubilizing agents and emulsifiers, such as ethyl alcohol, isopropylalcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzylbenzoate, propylene glycol, 1,3-butylene glycol, oils (in particular,cottonseed, groundnut, corn, germ, olive, castor and sesame oils),glycerol, tetrahydrofuryl alcohol, polyethylene glycols and fatty acidesters of sorbitan, and mixtures thereof.

Besides inert diluents, the oral compositions can also include adjuvantssuch as wetting agents, emulsifying and suspending agents, sweetening,flavoring, coloring, perfuming and preservative agents.

Suspensions, in addition to the active compounds, may contain suspendingagents as, for example, ethoxylated isostearyl alcohols, polyoxyethylenesorbitol and sorbitan esters, microcrystalline cellulose, aluminummetahydroxide, bentonite, agar-agar and tragacanth, and mixturesthereof.

Formulations of the pharmaceutical compositions of the invention forrectal or vaginal administration may be presented as a suppository,which may be prepared by mixing one or more compounds of the inventionwith one or more suitable nonirritating excipients or carrierscomprising, for example, cocoa butter, polyethylene glycol, asuppository wax or a salicylate, and which is solid at room temperature,but liquid at body temperature and, therefore, will melt in the rectumor vaginal cavity and release the active compound.

Formulations of the present invention which are suitable for vaginaladministration also include pessaries, tampons, creams, gels, pastes,foams or spray formulations containing such carriers as are known in theart to be appropriate.

Dosage forms for the topical or transdermal administration of a compoundof this invention include powders, sprays, ointments, pastes, creams,lotions, gels, solutions, patches and inhalants. The active compound maybe mixed under sterile conditions with a pharmaceutically-acceptablecarrier, and with any preservatives, buffers, or propellants which maybe required.

The ointments, pastes, creams and gels may contain, in addition to anactive compound of this invention, excipients, such as animal andvegetable fats, oils, waxes, paraffins, starch, tragacanth, cellulosederivatives, polyethylene glycols, silicones, bentonites, silicic acid,talc and zinc oxide, or mixtures thereof.

Powders and sprays can contain, in addition to a compound of thisinvention, excipients such as lactose, talc, silicic acid, aluminumhydroxide, calcium silicates and polyamide powder, or mixtures of thesesubstances. Sprays can additionally contain customary propellants, suchas chlorofluorohydrocarbons and volatile unsubstituted hydrocarbons,such as butane and propane.

Transdermal patches have the added advantage of providing controlleddelivery of a compound of the present invention to the body. Such dosageforms can be made by dissolving or dispersing the compound in the propermedium. Absorption enhancers can also be used to increase the flux ofthe compound across the skin. The rate of such flux can be controlled byeither providing a rate controlling membrane or dispersing the compoundin a polymer matrix or gel.

Ophthalmic formulations, eye ointments, powders, solutions and the like,are also contemplated as being within the scope of this invention.

Pharmaceutical compositions of this invention suitable for parenteraladministration comprise one or more compounds of the invention incombination with one or more pharmaceutically-acceptable sterileisotonic aqueous or nonaqueous solutions, dispersions, suspensions oremulsions, or sterile powders which may be reconstituted into sterileinjectable solutions or dispersions just prior to use, which may containsugars, alcohols, antioxidants, buffers, bacteriostats, solutes whichrender the formulation isotonic with the blood of the intended recipientor suspending or thickening agents.

Examples of suitable aqueous and nonaqueous carriers which may beemployed in the pharmaceutical compositions of the invention includewater, ethanol, polyols (such as glycerol, propylene glycol,polyethylene glycol, and the like), and suitable mixtures thereof,vegetable oils, such as olive oil, and injectable organic esters, suchas ethyl oleate. Proper fluidity can be maintained, for example, by theuse of coating materials, such as lecithin, by the maintenance of therequired particle size in the case of dispersions, and by the use ofsurfactants.

These compositions may also contain adjuvants such as preservatives,wetting agents, emulsifying agents and dispersing agents. Prevention ofthe action of microorganisms upon the subject compounds may be ensuredby the inclusion of various antibacterial and antifungal agents, forexample, paraben, chlorobutanol, phenol sorbic acid, and the like. Itmay also be desirable to include isotonic agents, such as sugars, sodiumchloride, and the like into the compositions. In addition, prolongedabsorption of the injectable pharmaceutical form may be brought about bythe inclusion of agents which delay absorption such as aluminummonostearate and gelatin.

In some cases, in order to prolong the effect of a drug, it is desirableto slow the absorption of the drug from subcutaneous or intramuscularinjection. This may be accomplished by the use of a liquid suspension ofcrystalline or amorphous material having poor water solubility. The rateof absorption of the drug then depends upon its rate of dissolutionwhich, in turn, may depend upon crystal size and crystalline form.Alternatively, delayed absorption of a parenterally-administered drugform is accomplished by dissolving or suspending the drug in an oilvehicle.

Injectable depot forms are made by forming microencapsule matrices ofthe subject compounds in biodegradable polymers such aspolylactide-polyglycolide. Depending on the ratio of drug to polymer,and the nature of the particular polymer employed, the rate of drugrelease can be controlled. Examples of other biodegradable polymersinclude poly(orthoesters) and poly(anhydrides). Depot injectableformulations are also prepared by entrapping the drug in liposomes ormicroemulsions which are compatible with body tissue.

When the compounds of the present invention are administered aspharmaceuticals, to humans and animals, they can be given per se or as apharmaceutical composition containing, for example, 0.1 to 99.5% (morepreferably, 0.5 to 90%) of active ingredient in combination with apharmaceutically acceptable carrier.

The preparations of the present invention may be given orally,parenterally, topically, or rectally. They are of course given in formssuitable for each administration route. For example, they areadministered in tablets or capsule form, by injection, inhalation, eyelotion, ointment, suppository, etc. administration by injection,infusion or inhalation; topical by lotion or ointment; and rectal bysuppositories. Oral administrations are preferred.

The phrases “parenteral administration” and “administered parenterally”as used herein means modes of administration other than enteral andtopical administration, usually by injection, and includes, withoutlimitation, intravenous, intramuscular, intraarterial, intrathecal,intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal,transtracheal, subcutaneous, subcuticular, intraarticulare, subcapsular,subarachnoid, intraspinal and intrasternal injection and infusion.

The phrases “systemic administration,” “administered systemically,”“peripheral administration” and “administered peripherally” as usedherein mean the administration of a compound, drug or other materialother than directly into the central nervous system, such that it entersthe patient's system and, thus, is subject to metabolism and other likeprocesses, for example, subcutaneous administration.

These compounds may be administered to humans and other animals fortherapy by any suitable route of administration, including orally,nasally, as by, for example, a spray, rectally, intravaginally,parenterally, intracisternally and topically, as by powders, ointmentsor drops, including buccally and sublingually.

Regardless of the route of administration selected, the compounds of thepresent invention, which may be used in a suitable hydrated form, and/orthe pharmaceutical compositions of the present invention, are formulatedinto pharmaceutically-acceptable dosage forms by conventional methodsknown to those of skill in the art.

Actual dosage levels of the active ingredients in the pharmaceuticalcompositions of this invention may be varied so as to obtain an amountof the active ingredient which is effective to achieve the desiredtherapeutic response for a particular patient, composition, and mode ofadministration, without being toxic to the patient.

The selected dosage level will depend upon a variety of factorsincluding the activity of the particular compound of the presentinvention employed, or the ester, salt or amide thereof, the route ofadministration, the time of administration, the rate of excretion ormetabolism of the particular compound being employed, the duration ofthe treatment, other drugs, compounds and/or materials used incombination with the particular compound employed, the age, sex, weight,condition, general health and prior medical history of the patient beingtreated, and like factors well known in the medical arts.

A physician or veterinarian having ordinary skill in the art can readilydetermine and prescribe the effective amount of the pharmaceuticalcomposition required. For example, the physician or veterinarian couldstart doses of the compounds of the invention employed in thepharmaceutical composition at levels lower than that required in orderto achieve the desired therapeutic effect and gradually increase thedosage until the desired effect is achieved.

In general, a suitable daily dose of a compound of the invention will bethat amount of the compound which is the lowest dose effective toproduce a therapeutic effect. Such an effective dose will generallydepend upon the factors described above. Generally, intravenous,intracerebroventricular and subcutaneous doses of the compounds of thisinvention for a patient, when used for the indicated analgesic effects,will range from about 0.0001 to about 100 mg per kilogram of body weightper day.

If desired, the effective daily dose of the active compound may beadministered as two, three, four, five, six or more sub-dosesadministered separately at appropriate intervals throughout the day,optionally, in unit dosage forms.

While it is possible for a compound of the present invention to beadministered alone, it is preferable to administer the compound as apharmaceutical formulation (composition).

In another aspect, the present invention provides pharmaceuticallyacceptable compositions which comprise a therapeutically-effectiveamount of one or more of the subject compounds, as described above,formulated together with one or more pharmaceutically acceptablecarriers (additives) and/or diluents. As described in detail below, thepharmaceutical compositions of the present invention may be speciallyformulated for administration in solid or liquid form, including thoseadapted for the following: (1) oral administration, for example,drenches (aqueous or non-aqueous solutions or suspensions), tablets,boluses, powders, granules, pastes for application to the tongue; (2)parenteral administration, for example, by subcutaneous, intramuscularor intravenous injection as, for example, a sterile solution orsuspension; (3) topical application, for example, as a cream, ointmentor spray applied to the skin, lungs, or oral cavity; or (4)intravaginally or intravectally, for example, as a pessary, cream orfoam; (5) sublingually; (6) ocularly; (7) transdermally; or (8) nasally.

The compounds according to the invention may be formulated foradministration in any convenient way for use in human or veterinarymedicine, by analogy with other pharmaceuticals.

The term “treatment” is intended to encompass also prophylaxis, therapyand cure.

The patient receiving this treatment is any animal in need, includingprimates, in particular humans, and other mammals such as equines,cattle, swine and sheep; and poultry and pets in general.

The compound of the invention can be administered as such or inadmixtures with pharmaceutically acceptable carriers and can also beadministered in conjunction with antimicrobial agents such aspenicillins, cephalosporins, aminoglycosides and glycopeptides.Conjunctive therapy, thus includes sequential, simultaneous and separateadministration of the active compound in a way that the therapeuticaleffects of the first administered one is not entirely disappeared whenthe subsequent is administered.

9. Combinatorial Libraries

The subject compounds readily lend themselves to the creation ofcombinatorial libraries for the screening of pharmaceutical,agrochemical or other biological or medically-related activity ormaterial-related qualities. A combinatorial library for the purposes ofthe present invention is a mixture of chemically related compounds whichmay be screened together for a desired property; said libraries may bein solution or covalently linked to a solid support. The preparation ofmany related compounds in a single reaction greatly reduces andsimplifies the number of screening processes which need to be carriedout. Screening for the appropriate biological, pharmaceutical,agrochemical or physical property may be done by conventional methods.

Diversity in a library can be created at a variety of different levels.For instance, the substrate aryl groups used in a combinatorial approachcan be diverse in terms of the core aryl moiety, e.g., a variegation interms of the ring structure, and/or can be varied with respect to theother substituents.

A variety of techniques are available in the art for generatingcombinatorial libraries of small organic molecules. See, for example,Blondelle et al. (1995) Trends Anal. Chem. 14:83; the Affymax U.S. Pat.Nos. 5,359,115 and 5,362,899: the Ellman U.S. Pat. No. 5,288,514: theStill et al. PCT publication WO 94/08051; Chen et al. (1994) JACS116:2661: Kerr et al. (1993) JACS 115:252; PCT publications WO92/10092,WO93/09668 and WO91/07087; and the Lerner et al. PCT publicationWO93/20242). Accordingly, a variety of libraries on the order of about16 to 1,000,000 or more diversomers can be synthesized and screened fora particular activity or property.

In an exemplary embodiment, a library of substituted diversomers can besynthesized using the subject reactions adapted to the techniquesdescribed in the Still et al. PCT publication WO 94/08051, e.g., beinglinked to a polymer bead by a hydrolyzable or photolyzable group, e.g.,located at one of the positions of substrate. According to the Still etal. technique, the library is synthesized on a set of beads, each beadincluding a set of tags identifying the particular diversomer on thatbead. In one embodiment, which is particularly suitable for discoveringenzyme inhibitors, the beads can be dispersed on the surface of apermeable membrane, and the diversomers released from the beads by lysisof the bead linker. The diversomer from each bead will diffuse acrossthe membrane to an assay zone, where it will interact with an enzymeassay. Detailed descriptions of a number of combinatorial methodologiesare provided below.

A) Direct Characterization

A growing trend in the field of combinatorial chemistry is to exploitthe sensitivity of techniques such as mass spectrometry (MS), e.g.,which can be used to characterize sub-femtomolar amounts of a compound,and to directly determine the chemical constitution of a compoundselected from a combinatorial library. For instance, where the libraryis provided on an insoluble support matrix, discrete populations ofcompounds can be first released from the support and characterized byMS. In other embodiments, as part of the MS sample preparationtechnique, such MS techniques as MALDI can be used to release a compoundfrom the matrix, particularly where a labile bond is used originally totether the compound to the matrix. For instance, a bead selected from alibrary can be irradiated in a MALDI step in order to release thediversomer from the matrix, and ionize the diversomer for MS analysis.

B) Multipin Synthesis

The libraries of the subject method can take the multipin libraryformat. Briefly, Geysen and co-workers (Geysen et al. (1984) PNAS81:3998-4002) introduced a method for generating compound libraries by aparallel synthesis on polyacrylic acid-grated polyethylene pins arrayedin the microtitre plate format. The Geysen technique can be used tosynthesize and screen thousands of compounds per week using the multipinmethod, and the tethered compounds may be reused in many assays.Appropriate linker moieties can also been appended to the pins so thatthe compounds may be cleaved from the supports after synthesis forassessment of purity and further evaluation (c.f., Bray et al. (1990)Tetrahedron Lett 31:5811-5814; Valerio et al. (1991) Anal Biochem197:168-177; Bray et al. (1991) Tetrahedron Lett 32:6163-6166).

C) Divide-Couple-Recombine

In yet another embodiment, a variegated library of compounds can beprovided on a set of beads utilizing the strategy ofdivide-couple-recombine (see, e.g., Houghten (1985) PNAS 82:5131-5135;and U.S. Pat. Nos. 4,631,211; 5,440,016; 5,480,971). Briefly, as thename implies, at each synthesis step where degeneracy is introduced intothe library, the beads are divided into separate groups equal to thenumber of different substituents to be added at a particular position inthe library, the different substituents coupled in separate reactions,and the beads recombined into one pool for the next iteration.

In one embodiment, the divide-couple-recombine strategy can be carriedout using an analogous approach to the so-called “tea bag” method firstdeveloped by Houghten, where compound synthesis occurs on resin sealedinside porous polypropylene bags (Houghten et al. (1986) PNAS82:5131-5135). Substituents are coupled to the compound-bearing resinsby placing the bags in appropriate reaction solutions, while all commonsteps such as resin washing and deprotection are performedsimultaneously in one reaction vessel. At the end of the synthesis, eachbag contains a single compound.

D) Combinatorial Libraries by Light-Directed, Spatially AddressableParallel Chemical Synthesis

A scheme of combinatorial synthesis in which the identity of a compoundis given by its locations on a synthesis substrate is termed aspatially-addressable synthesis. In one embodiment, the combinatorialprocess is carried out by controlling the addition of a chemical reagentto specific locations on a solid support (Dower et al. (1991) Annu RepMed Chem 26:271-280; Fodor, S. P. A. (1991) Science 251:767; Pirrung etal. (1992) U.S. Pat. No. 5,143,854; Jacobs et al. (1994) TrendsBiotechnol 12:19-26). The spatial resolution of photolithography affordsminiaturization. This technique can be carried out through the use ofprotection/deprotection reactions with photolabile protecting groups.

The key points of this technology are illustrated in Gallop et al.(1994) J Med Chem 37:1233-1251. A synthesis substrate is prepared forcoupling through the covalent attachment of photolabilenitroveratryloxycarbonyl (NVOC) protected amino linkers or otherphotolabile linkers. Light is used to selectively activate a specifiedregion of the synthesis support for coupling. Removal of the photolabileprotecting groups by light (deprotection) results in activation ofselected areas. After activation, the first of a set of amino acidanalogs, each bearing a photolabile protecting group on the aminoterminus, is exposed to the entire surface. Coupling only occurs inregions that were addressed by light in the preceding step. The reactionis stopped, the plates washed, and the substrate is again illuminatedthrough a second mask, activating a different region for reaction with asecond protected building block. The pattern of masks and the sequenceof reactants define the products and their locations. Since this processutilizes photolithography techniques, the number of compounds that canbe synthesized is limited only by the number of synthesis sites that canbe addressed with appropriate resolution. The position of each compoundis precisely known; hence, its interactions with other molecules can bedirectly assessed.

In a light-directed chemical synthesis, the products depend on thepattern of illumination and on the order of addition of reactants. Byvarying the lithographic patterns, many different sets of test compoundscan be synthesized simultaneously; this characteristic leads to thegeneration of many different masking strategies.

E) Encoded Combinatorial Libraries

In yet another embodiment, the subject method utilizes a compoundlibrary provided with an encoded tagging system. A recent improvement inthe identification of active compounds from combinatorial librariesemploys chemical indexing systems using tags that uniquely encode thereaction steps a given bead has undergone and, by inference, thestructure it carries. Conceptually, this approach mimics phage displaylibraries, where activity derives from expressed peptides, but thestructures of the active peptides are deduced from the correspondinggenomic DNA sequence. The first encoding of synthetic combinatoriallibraries employed DNA as the code. A variety of other forms of encodinghave been reported, including encoding with sequenceable bio-oligomers(e.g., oligonucleotides and peptides), and binary encoding withadditional non-sequenceable tags.

(1) Tagging with Sequenceable Bio-Oligomers:

The principle of using oligonucleotides to encode combinatorialsynthetic libraries was described in 1992 (Brenner et al. (1992) PNAS89:5381-5383), and an example of such a library appeared the followingyear (Needles et al. (1993) PNAS 90:10700-10704). A combinatoriallibrary of nominally 7⁷ (=823,543) peptides composed of all combinationsof Arg, Gln, Phe, Lys, Val, D-Val and Thr (three-letter amino acidcode), each of which was encoded by a specific dinucleotide (TA, TC, CT,AT, TT, CA and AC, respectively), was prepared by a series ofalternating rounds of peptide and oligonucleotide synthesis on solidsupport. In this work, the amine linking functionality on the bead wasspecifically differentiated toward peptide or oligonucleotide synthesisby simultaneously preincubating the beads with reagents that generateprotected OH groups for oligonucleotide synthesis and protected NH₂groups for peptide synthesis (here, in a ratio of 1:20). When complete,the tags each consisted of 69-mers, 14 units of which carried the code.The bead-bound library was incubated with a fluorescently labeledantibody, and beads containing bound antibody that fluoresced stronglywere harvested by fluorescence-activated cell sorting (FACS). The DNAtags were amplified by PCR and sequenced, and the predicted peptideswere synthesized. Following such techniques, compound libraries can bederived for use in the subject method, where the oligonucleotidesequence of the tag identifies the sequential combinatorial reactionsthat a particular bead underwent, and therefore provides the identity ofthe compound on the bead.

The use of oligonucleotide tags permits exquisitely sensitive taganalysis. Even so, the method requires careful choice of orthogonal setsof protecting groups required for alternating co-synthesis of the tagand the library member. Furthermore, the chemical lability of the tag,particularly the phosphate and sugar anomeric linkages, may limit thechoice of reagents and conditions that can be employed for the synthesisof non-oligomeric libraries. In preferred embodiments, the librariesemploy linkers permitting selective detachment of the test compoundlibrary member for assay.

Peptides have also been employed as tagging molecules for combinatoriallibraries. Two exemplary approaches are described in the art, both ofwhich employ branched linkers to solid phase upon which coding andligand strands are alternately elaborated. In the first approach (Kerr JM et al. (1993) J Am Chem Soc 115:2529-2531), orthogonality in synthesisis achieved by employing acid-labile protection for the coding strandand base-labile protection for the compound strand.

In an alternative approach (Nikolaiev et al. (1993) Pept Res 6:161-170),branched linkers are employed so that the coding unit and the testcompound can both be attached to the same functional group on the resin.In one embodiment, a cleavable linker can be placed between the branchpoint and the bead so that cleavage releases a molecule containing bothcode and the compound (Ptek et al. (1991) Tetrahedron Lett32:3891-3894). In another embodiment, the cleavable linker can be placedso that the test compound can be selectively separated from the bead,leaving the code behind. This last construct is particularly valuablebecause it permits screening of the test compound without potentialinterference of the coding groups. Examples in the art of independentcleavage and sequencing of peptide library members and theircorresponding tags has confirmed that the tags can accurately predictthe peptide structure.

(2) Non-Sequenceable Tagging—Binary Encoding:

An alternative form of encoding the test compound library employs a setof non-sequenceable electrophoric tagging molecules that are used as abinary code (Ohlmeyer et al. (1993) PNAS 90:10922-10926). Exemplary tagsare haloaromatic alkyl ethers that are detectable as theirtrimethylsilyl ethers at less than femtomolar levels by electron capturegas chromatography (ECGC). Variations in the length of the alkyl chain,as well as the nature and position of the aromatic halide substituents,permit the synthesis of at least 40 such tags, which in principle canencode 2⁴⁰ (e.g., upwards of 10¹²) different molecules. In the originalreport (Ohlmeyer et al., supra) the tags were bound to about 1% of theavailable amine groups of a peptide library via a photocleavableo-nitrobenzyl linker. This approach is convenient when preparingcombinatorial libraries of peptide-like or other amine-containingmolecules. A more versatile system has, however, been developed thatpermits encoding of essentially any combinatorial library. Here, thecompound would be attached to the solid support via the photocleavablelinker and the tag is attached through a catechol ether linker viacarbene insertion into the bead matrix (Nestler et al. (1994) J Org Chem59:4723-4724). This orthogonal attachment strategy permits the selectivedetachment of library members for assay in solution and subsequentdecoding by ECGC after oxidative detachment of the tag sets.

Although several amide-linked libraries in the art employ binaryencoding with the electrophoric tags attached to amine groups, attachingthese tags directly to the bead matrix provides far greater versatilityin the structures that can be prepared in encoded combinatoriallibraries. Attached in this way, the tags and their linker are nearly asunreactive as the bead matrix itself. Two binary-encoded combinatoriallibraries have been reported where the electrophoric tags are attacheddirectly to the solid phase (Ohlmeyer et al. (1995) PNAS 92:6027-6031)and provide guidance for generating the subject compound library. Bothlibraries were constructed using an orthogonal attachment strategy inwhich the library member was linked to the solid support by aphotolabile linker and the tags were attached through a linker cleavableonly by vigorous oxidation. Because the library members can berepetitively partially photoeluted from the solid support, librarymembers can be utilized in multiple assays. Successive photoelution alsopermits a very high throughput iterative screening strategy: first,multiple beads are placed in 96-well microtiter plates; second,compounds are partially detached and transferred to assay plates; third,a metal binding assay identifies the active wells; fourth, thecorresponding beads are rearrayed singly into new microtiter plates;fifth, single active compounds are identified; and sixth, the structuresare decoded.

EXEMPLIFICATION

The invention now being generally described, it will be more readilyunderstood by reference to the following examples, which are includedmerely for purposes of illustration of certain aspects and embodimentsof the present invention, and are not intended to limit the invention.

General Methods and Materials

All HPLC experiments were performed on a Varian Prostar HPLC equippedwith Autosampler (Model 410), UV-visible detector (Model 345), NaIradiometic detector, and Prostar Pumps (model 210). The preparation ofthe 0.05 M Triethylammonium phosphate pH 2.25 HPLC solvent was performedby adding 7 mL of triethylamine to 500 ml of H₂O. This was followed bythe addition of 4 ml of phosphoric acid to reach the desired 2.25 pH.The solution was diluted to 1000 ml with H₂O and filtered through a 0.22μm cellulose filter into a 1 liter HPLC bottle. The solution wassonicated for 10 minutes to degas.

Technetium-99m was used as a Na^(99m)TcO₄ solution in saline, as acommercial ⁹⁹Mo/^(99m)Tc generator eluant (Cardinal Health).Technetium-99m (^(99m)Tc) is a γ emitter (141 keV) with a half-life of 6h. The ^(99m)Tc-containing solutions were always kept behind sufficientlead shielding. The use of [^(99m)Tc(CO)₃(H₂O)₃]⁺ was prepared fromcommercially available Isolink™ kits (Mallinckrodt). TheTc-99m-complexes were prepared and injected as a 10% ethanol/salinesolutions.

The animal care and use procedures were in accordance with the Guide forthe Care and Use of Laboratory Animals and the Animal Welfare Act. Thevertebrate animals in this research project were used to investigate thebiodistribution and pharmacokinetics of the rotenone derivatives anddetermine uptake in the heart. Rats (Sprague Dawley, male, at 80-100grams each) were used for the whole body biodistribution studies. TheTc-complexes, as well as Cardiolite™, were evaluated at three timepoints; 5, 30, and 120 minutes, with five animals per time point. Inorder to provide accurate statistics in the clearance rate measurementsand to account for intra-species variation it was necessary to use thisnumber of animals. The product was diluted to ˜10 μCi/100 μl usingfreshly prepared 10% ethanol/saline (0.9%) solution. The rats wereinjected via a lateral tail vein with a volume of 0.1 mL. The rats weresacrificed by decapitation, with immediate blood collection at thedesired time points. Whole body biodistributions were performed on theanimals immediately following decapitation, organ and tissue sampleswere taken and washed of excess blood, blotted dry and weighed.Radioactivity was assayed using automated NaI well counter. All tissuesamples were counted together along with an aliquot of the injected doseso that % injected dose and % injected dose per gram of tissue could becalculated. The data are reported as % ID/g.

Example 1 Synthesis of [N-{ethyl-2-dimethoxy}-2-imidazolecarboxaldehyde]

2-imidazolecarboxaldehyde (2.0 g, 0.021 mol) was placed in a 15 mLpressure tube equipped with a stirrer under argon. The solution wasdissolved in 2 mL of DMF, followed by addition of potassium carbonate(0.50 g, 3.6 mmol), and bromoacetaldelhyde dimethyl acetal (03.87 g,0.023 mmol). The solution was heated at 120° C. for 20 hrs. The solutionwas then vacuumed down to residue. The residue was passed through a HPLCsilca gel column using 0-10% methanol/methylene chloride as thesolvents, yielding 1.15 g, 30.1% yield. ¹H NMR (CDCl₃), 300 MHz): 3.37(s, 6H), 4.47 (m, 2H), 7.20 (s, H), 7.25 (s, H), 9.78 (s, H).

Example 2 Synthesis of[N-{ethyl-2-dimethoxy}-2-methyl-imidazole-3,4,5-trimethoxy-benzylamine]

Placed 3,4,5-trimethoxy-benzylamine (0.054 g, 0.027 mol) in a 100 mLround-bottom flask equipped with a stirrer under nitrogen. The liquidwas dissolved in 8 mL of dichloroethane, followed by addition of[N-{ethyl-2-dimethoxy}-2-imidazolecarboxaldehyde] (0.10 g, 0.054 mmol)and sodium triacetoxyborohydride (0.127 g, 0.059 mmol). The solution wasstirred at room temperature for 18 hours. The solution was then vacuumeddown to residue. The residue was passed through a HPLC silca gel columnusing 0-5% methanol/methylene chloride as the solvents, yielding 0.124g, 85.5% yield. ¹H NMR ((CDCl₃), 300 MHz): 3.21 (s, 12H), 3.54 (s, 2H),3.72 (s, 4H), 3.80 (s, 3H), 3.82 (s, 6H), 3.87 (d, 4H), 4.20 (t, 2H),6.43 (s, 2H), 6.92 (d, 2H). GCMS=535 (M+1).

Example 3 Synthesis of[N-{ethyl-2-diethoxy}-2-methyl-imidazole-3,4,5-trimethoxy-benzylamine]

Placed 3,4,5-trimethoxy-benzylamine (0.1 g, 0.508 mmol) in a 100 mlround-bottom flask equipped with a stirrer under nitrogen. The liquidwas dissolved in 8 ml of dichloroethane, followed by addition of[N-{ethyl-2-diethoxy}-2-imidazolecarboxaldehyde] (0.216 g, 1.01 mmol)and sodium triacetoxyborohydride (0.237 g, 1.12 mmol). The solution wasstirred at room temperature for 18 hours. The solution was then vacuumeddown to residue. The residue was passed through a HPLC silca gel columnusing 0-5% methanol/methylene chloride as the solvents, yielding 0.124g, 41.3% yield. ¹H NMR ((CDCl₃), 300 MHz): 1.09 (t, 12H), 3.25 (in, 4H),3.55 (m, 4H), 3.78 (m, 4H), 3.80 (m, 9H), 3.95 (d, 4H), 4.33 (t, 2H),4.65 (d, 2H), 6.46 (s, 2H), 6.90 (d, 2H), 6.97 (d, 2H). GCMS 592-593(M:M+1).

Example 4 Synthesis of[N,N′-{N-ethyl-2-diethoxy}-2-methyl-imidazole}-N,N′-bis(2-hydroxybenzyl)-ethylenediamine]

Placed N,N′-Bis(2-hydroxybenzyl)ethylenediamine (0.1 g, 0.367 mmol) in a100 ml round-bottom flask equipped with a stirrer under nitrogen. Thesolid was dissolved in 8 ml of dichloroethane, followed by addition of[N-{ethyl-2-diethoxy}-2-imidazolecarboxaldehyde] (0.165 g, 0.775 mmol)and sodium triacetoxyborohydride (0.178 g, 0.845 mmol). The solution wasstirred at room temperature for 18 hours. The solution was then vacuumeddown to residue. The residue was passed through a silca gel column using0-20% methanol/methylene chloride as the solvents, yielding 0.049 g,20.1% yield. ¹H NMR ((CDCl₃), 300 MHz): 1.10 (t, 12H), 2.10 (s, 8H),2.77 (s, 2H), 3.34 (m, 4H), 3.58 (m, 4H), 3.77 (s, 2H), 3.84 (d, 2H),4.45 (t, 2H), 6.72 (t, 2H), 6.85 (m, 8H), 6.96 (s, 2H), 7.13 (t, 2H).ES/MS=666-668: expected 668.

Example 5 Synthesis of [N-ethyl-ethoxy-dipyridine-2-methylamine]

Placed 2-di-(picoline)amine (0.50 g, 2.51 mmol) and 1-bromoethyl-ethoxy(0.420 g, 2.76 mmol) in a 100 ml pressure tube with a stir bar. Thesolids were dissolved in 2 ml of dried DMF. Potassium carbonate (0.05 g,0.362 mmol) and NEt₃ (1 mL) were added to the solution. The solution washeated at 125° C. for 4 hrs. and then vacuumed down to residue. Theresidue was passed through a silca gel column using 2%methanol/methylene chloride as the solvents. The product was eluted as ayellow oil (0.568 g, 83.3%). ¹H NMR (CDCl₃), 300 MHz): 1.12 (t, 3H),2.79 (t, H), 2.84 (s, 2H), 2.91 (s, 2H), 3.39 (q, H), 3.52 (t, H), 3.87(s, 2H), 5.24 (s, H), 7.11 (t, 2H), 7.54 (m, 2H), 7.60 (m, H), 7.97 (s,H), 8.47 (d, 2H). GCMS=M.W. 273. Calc. M.W.=272.

Example 6 Synthesis of [N-ethyl-dimethoxy-dipyridine-2-methylamine]

The dipyridine-2-methylamine (0.50 g, 2.51 mmol) was placed in a 15 mlpressure tube equipped with a stirrer. The solution was dissolved in 3ml of DMF, 2 ml of triethylamine, followed by addition of potassiumcarbonate (0.10 g, 0.72 mmol), and the 2-bromo-1,1-dimethoxy-ethane(0.47 g, 2.76 mmol). The solution was heated at 110° C. for 1 hrs. Thesolution was then vacuumed down to residue. The residue was passedthrough a HPLC silca gel column using 0-10% methanol/methylene chlorideas the solvents, yielding 0.25 g, 34.7% yield. ¹H NMR ((CDCl₃), 300MHz): 2.77 (d, 2H), 3.28 (s, 6H), 3.92 (s, 4H), 4.53 (t, H), 7.12 (t,2H), 7.55 (d, 2H), 7.65 (m, 2H), 8.51 (d, 2H), GC/MS=288 (M+1).

Example 7 Synthesis of [N-ethyl-diethoxy-dipyridine-2-methylamine]

The dipyridine-2-methylamine (0.50 g, 2.51 mmol) was placed in a 15 mlpressure tube equipped with a stirrer. The solution was dissolved in 3ml of DMF, 2 ml of triethylamine, followed by addition of potassiumcarbonate (0.10 g, 0.72 mmol), and the 2-bromo-1,1-diethoxy-ethane (0.54g, 2.76 mmol). The solution was heated at 130° C. for 1 hrs. Thesolution was then vacuumed down to residue. The residue was passedthrough a HPLC silca gel column using 0-10% methanol/methylene chlorideas the solvents, yielding 0.51 g, 64.6% yield. ¹H NMR ((CDCl₃), 300MHz): 1.14 (t, 6H), 2.77 (d, 2H), 3.44 (m, 2H), 3.59 (m, 2H), 3.92 (s,4H), 4.63 (t, H), 7.11 (dd, 2H), 7.56 (d, 2H), 7.64 (m, 2H), 8.48 (d,2H), GC/MS=316.

Example 8 Synthesis of [N-3,5-dimethoxybenzyl-dipyridine-2-methylamine]

Placed 2-di-(picoline)amine (0.50 g, 2.51 mmol) and 3,5-dimethoxybenzylbromide (0.698 g, 3.02 mmol) in a 100 ml pressure tube with a stir bar.The solids were dissolved in 2 ml of dried DMF. Potassium carbonate(0.05 g, 0.362 mmol) and NEt₃ (1 mL) were added to the solution. Thesolution was heated at 125° C. for 1.5 hrs. and then vacuumed down toresidue. The residue was passed through a silca gel column using 2%methanol/methylene chloride as the solvents. The product was eluted as ayellow oil (0.50 g, 57.1%). ¹H NMR (CDCl₃), 300 MHz): 2.83 (s, 2H), 2.89(s, 2H), 3.61 (s, 2H), 3.74 (s, 3H), 3.78 (s, 3H), 6.31 (t, H), 6.58 (d,2H), 7.09 (t, 2H), 7.59 (m, 4H), 8.47 (d, 2H). GCMS=M.W. 351. Calc.M.W.=349.

Example 9 Synthesis of (C₅H₄NCH₂)₂NH

In a 100 mL round bottomed flask was placed 2-aminomethylpyridine (2.50g, 0.023 moles). The system was placed under nitrogen. The solid wasdissolved in 20 mL of acetonitrile followed by the addition of 7 mL oftriethylamine. Next the 2-bromomethylpyridine hydrobromide (5.80 g,0.023 moles) was added. The reaction mixture was allowed to stir for 0.5hours at 55 C., whereupon the reaction was vacuumed down to residue. Themixture was purified using a large silica column (10% methanol/methylenechloride). ¹H NMR (CDCl₃, ppm): 2.97 (s, H), 3.98 (s, 4H), 7.15 (m, 2H),7.28 (in, 2H), 7.65 (m, 2H), 8.55 (m, 2H). Mass Spectroscopydemonstrated the molecular weight to be 199.

Example 10 Synthesis of (C₅H₄NCH₂)₃N

In a 100 mL round bottomed flask was placed 2-aminomethylpyridine (2.50g, 0.023 moles). The system was placed under nitrogen. The solid wasdissolved in 20 mL of acetonitrile followed by the addition of 7 mL oftriethylamine. Next the 2-bromomethylpyridine hydrobromide (5.80 g,0.023 moles) was added. The reaction mixture was allowed to stir for 0.5hours at 55 C., whereupon the reaction was vacuumed down to residue. Themixture was purified using a large silica column (10% methanol/methylenechloride). ¹H NMR (CDCl₃, ppm): 3.98 (s, 4H), 7.15 (m, 2H), 7.55 (m,2H), 7.65 (m, 2H), 8.55 (m, 2H). Mass Spectroscopy demonstrated themolecular weight to be 291 (M+1).

Example 11 Synthesis of (C₅H₄NCH₂)₂NCH₃

In a 100 mL round bottomed flask was placed dipyridinemethylamine DPMA(1.00 g, 5.03 mmoles). The solid was dissolved in 10 mL of acetonitrilefollowed by the addition of 2 mL of dimethylformamide. Next themethyliodide (0.637 g, 4.52 mmoles) was added. The reaction mixture wasallowed to stir for 0.5 hours at room temperature, whereupon thereaction was vacuumed down to residue. The mixture was purified using alarge silica column (10% methanol/methylene chloride). ¹H NMR (CDCl₃,ppm): 2.19 (s, 3H), 3.85 (s, 4H), 7.15 (m, 2H), 7.50 (d, 2H), 7.65 (m,2H), 8.55 (d, 2H). Mass Spectroscopy demonstrated the molecular weightto be 214 (M+1).

Example 12 Synthesis of (C₅H₄NCH₂NCH₂COOH) {(CH₂CH₂CH₂N(CH₃)₃}

In a 100 mL round bottomed flask was placed pyridinemethylaminemonoacetic acid (PAMA) (0.30 g, 1.55 mmoles). The solid was dissolved in10 mL of acetonitrile followed by the addition of 5 mL ofdimethylformamide. Next, two equivalents of the iodine salt of1-chloropropyltrimethylamine (0.815 g, 3.10 mmoles) was added. Finally,potassium carbonate (0.10 g, 0.724 mmol) was added. The reaction mixturewas heated at 130° C. for 3 hours, whereupon the reaction was vacuumeddown to residue. The mixture was purified using a reverse phase C18column (99% H₂O/1% CH₃CN). ¹H NMR (CDCl₃, ppm): 2.20 (s, 2H), 3.05 (s,2H), 3.14 7 (s, 9H), 3.34 (m, 2H), 4.28 (s, 2H), 7.60 (d, 2H), 7.70 (d,2H), 8.1 (d, 2H), 8.65 (d, 2H).

Example 13 Synthesis of (C₅H₄NCH₂NCH₂COOH)(CH₂(CH₂)₁₀COOH)

This compound was prepared using the same synthetic protocol as in thesynthesis of (C₅H₄NCH₂NCH₂COOH) {(CH₂CH₂CH₂N(CH₃)₃}. See Example 12. ¹HNMR (CDCl₃, ppm): 1.25 (m, 10H), 1.45 (s, 2H), 1.60 (s, 2H), 1.75 (m,2H), 2.3 (m, 2H), 2.55 (m, 2H), 3.63 (s, 3H), 3.80 (s, 2H), 7.05 (dd,2H), 7.55 (d, 2H), 7.65 (dd, 2H), 8.53 (d, 2H).

Example 14 Synthesis of (C₅H₄NCH₂)₂N(CH₂COOCH₂CH₃)

This compound was prepared using the same synthetic protocol as in thesynthesis of (C₅H₄NCH₂NCH₂COOH){(CH₂CH₂CH₂N(CH₃)₃}. See Example 12.However, DPMA was used in place of PAMA. ¹H NMR (CDCl₃, ppm): 1.25 (t,3H), 3.45 (s, 2H), 3.95 (s, 4H), 4.15 (q, 2H), 7.1 (m, 2H), 7.55 (m,4H), 8.53 (s, 2H).

Example 15 (Bis(2-pyridylmethyl)amino)acetic Acid

2-Chloromethylpyridine hydrochloride (9.2 g, 8.53 mmol) and glycin (2 g,26.6 mmol) were dissolved in water (30 mL) and stirred at roomtemperature for five days, with addition of 5 mol aqueous NaOH solutionat intervals to maintain the pH at 8-10. The resulting dark red solutionwas extracted with ethyl acetate, neutralized with HCl and concentrated.The residue was dissolved in dichloromethane, and the insoluble sodiumchloride was filtered. Pale yellow crystals formed from the filtrate,which were collected and dried under vacuum. Yield (2.87 g) (11.2 mmol,42%). ¹H NMR (CDCl₃), 300 MHz): 3.39 (s, 2H), 3.98 (s, 4H), 7.06 (t,2H), 7.30 (d, 2h), 7.56 (t, 2H), 8.36 (d, 2H). ¹³C NMR (CD₃OD, 300 MHz):57.36 (C, CH₂), 59.77 (2C, PyCH₂), 124.77 (2CH, Py), 125.15 (2CH, Py),139.00 (C, CH₂), 149.76 (2CH, Py), 156.10 (2C, Py), 173.05 (C, CO₂H).

Example 16 (Bis(2-pyridylmethyl)amino)propionic Acid

This compound was synthesized by a similar procedure as described asabove, except that 3-aminopropionic acid was used instead of glycine.The product was collected as pale red crystals from dichloromethane.Yield (2.74 g, 10.1 mmol, 45%). ¹H NMR (CDCl₃), 300 MHz): 2.64 (t, 2H),3.03 (t, 2H), 3.95 (s, 4H), 7.21 (t, 2H), 7.38 (d, 2H), 8.55 (t, 2H),8.66 (d, 2H). ¹³C NMR (CD₃OD, 300 MHz): 33.15 (C, CH₂), 51.90 (C, NCH₂),60.22 (2C, PyCH₂), 124.37 (2CH, Py), 125.29 (2CH, Py), 138.98 (2C, Py),149.72 (2CH, Py), 158.50 (2C, Py), 176.79 (C, CO₂H).

Example 17 Ethyl-(bis(2-pyridylmethyl)amino)acetate

(Bis(2-pyridylmethyl)amino)acetic acid (1 g, 3.89 mmol) was taken insaturated ethanolic HCl (20 mL) and refluxed for 3 h. The reactionmixture was quenched with triethylamine and concentrated. The residuewas dissolved in dichloromethane, washed with water, dried (Na₂SO4) andconcentrated. The residue was purified on silica gel columnchromatography using methanol: chloroform (3:97) to giveEthyl-(bis(2-pyridylmethyl)amino)acetate as viscous liquid. Yield (0.910g, 3.19 mmol, 82%). ¹H NMR (CDCl₃), 300 MHz): 1.22 (t, 2H), 3.42 (s,2H), 3.97 (s, 4H), 4.12 (q, 2H), 7.12 (t, 2H), 7.53 (d, 2H), 7.62 (t,2H), 8.49 (d, 2H). ¹³C NMR (CD₃OD, 300 MHz): 13.99 (C, CH₃), 54.67 (C,CH₂), 59.70 (2C, PyCH₂), 60.21 (2C, OCH₂), 121.88 (2CH, Py), 122.93(2CH, Py), 136.32 (2CH, Py), 148.80 (2CH, Py), 158.80 (2C, Py), 171.05(C, CO₂H).

Example 18 Ethyl-(bis(2-pyridylmethyl)amino)propionate

This compound was synthesized by a similar procedure as described above,except that (Bis(2-pyridylmethyl)amino)propionic acid was used insteadof (Bis(2-pyridylmethyl)amino)acetic acid. The product was collected asa viscous liquid. Yield (1.37 g, 4.59 mmol, 83%). ¹H NMR (CDCl₃), 300MHz): 1.09 (t, 3H), 2.45 (t, 2H), 2.84 (t, 2H), 3.74 (s, 4H), 3.98 (q,2H), 7.03 (t, 2H), 7.39 (d, 2H), 7.51 (t, 2H), 8.48 (d, 2H). ¹³C NMR(CD₃OD, 300 MHz): 13.70 (C, CH₃), 32.22 (C, CH₂) 49.39 (C, NCH₂), 59.45(2C, PyCH₂), 59.55 (C, OCH₂), 121.47 (2CH, Py), 122.42 (2CH, Py), 135.82(2CH, Py), 148.40 (2CH, Py), 158.91 (2C, Py), 171.74 (C, CO₂H).

Example 19 Synthesis ofN-α-(tert-Butoxycarbonyl)-N-ω-bis(2-pyridylmethyl)-L-lysine (L1c-Boc)

2-Chloromethylpyridine hydrochloride (1.4 g, 8.53 mmol) andN-α-(tert-Butoxycarbonyl)-L-lysine (1 g, 4.06 mmol) were dissolved inwater and stirred at room temperature for five days, with addition of 5mol dm⁻³ aqueous NaOH solution at intervals to maintain the pH at 8-10.The resulting dark red solution was extracted with ethyl acetate, andthen the aqueous phase was acidified to pH 3-4 by 1 mol dm⁻³ HCl andextracted with Chloroform and concentrated. This residue purified bycolumn chromatography using 10% chloroform in methanol to giveN-α-(tert-Butoxycarbonyl)-N-co-bis(2-pyridylmethyl)-L-lysine (950 mg,55%). ¹H NMR (CDCl₃), 300 MHz): 1.41 (s, 9H), 1.26-1.62 (m, 6H), 2.58(t, 2H), 3.84 (s, 4H), 4.24 (t, H), 7.15 (m, 2H), 7.48 (d, 2H), 7.65 (m,2H), 8.53 (d, 2H). ¹³C NMR (CD₃OD, 300 MHz): 24.31 (C, CH₂), 26.66 (C,CH₂), 28.93 (3C, t-Bu), 33.15 (C, CH₂), 55.50 (C, NCH₂), 60.12 (2C,PyCH₂), 80.06 (C, NCH) 124.34 (2C, Py), 125.11 (2CH, Py), 138.93 (2CH,Py), 149.72 (2CH, Py), 157.71 (2C, Py), 177.49 (C, CO₂H).

Example 20 Synthesis ofN-α-(2-pyridylmethyl)-N-ω-(tert-Butoxycarbonyl)-L-lysine (L2d-Boc)

2-Chloromethylpyridine hydrochloride (730 mg, 4.46 mmol) andN-α-(tert-Butoxycarbonyl)-L-lysine (1 g, 4.06 mmol) were dissolved inwater and stirred at room temperature for two days, with addition of 5mol dm⁻³ aqueous NaOH solution at intervals to maintain the pH at 8-10.The resulting dark red solution was extracted with ethyl acetate, andthen the aqueous phase was acidified to pH 6 by 1 mol dm⁻³ HCl andfollowed by treating with chloroform the required product precipitateout, which was filtered and dried under vacuum (670 mg, 49%).

Example 21 Labeling the DIMA and DPMA Analogs with Tc-99m Using LabelingMethods Based on the Tc(V)-Oxo and Tc(I)(CO)₃L₃ Cores

Tc(V)-Oxo Core

Preparation of the Tc-99m-labeled DPMA derivatives was achieved byadding 10 mCi of TcO₄ ⁻ to a 0.9% saline solution of the DPMA derivative(200 mg/3 mL). The mixture was heated at 80° C. for 30 min. Depending onthe biological ligand, the solution was used as needed or the mixturewas extracted with ethyl acetate (3, 1 mL portions), dried over sodiumsulfate, and dried under N₂. The residue was then re-dissolved inethanol (400 uL) and purity checked via HPLC by a Vydac C18 (5 mm, 25cm) column using methanol to elute the reaction products.

Tc(I)(CO)₃+ Core

The Tc(I) carbonyl chemistry allows for the possibility of analternative route to form stable ^(99m)Tc-DIMA and DPMA complexes. Thetechnetium labeling was accomplished using the Tc(I)-tricarbonylmethods. The Tc(I)(CO)₃ ⁺ core was readily formed using the Isolink™ kit(Mallinkrodt). The [^(99m)Tc(CO)₃(H₂O)₃]⁺ starting material was formedby adding 1 ml of TcO₄ ⁻ in saline to an Isolink™ kit. The solution washeated at 100° C. for 30 minutes, followed by the addition of 120 μl of1N HCl to neutralize the solution. The [^(99m)Tc(CO)₃(H₂O)₃]⁺ (200 μl)was added to the appropriate derivative in 0.2 ml (1 mg/ml) of methanoland heated at 80° C. for 1 hour.

Analysis of the reaction products using C18 HPLC, showed >60% RCP forall complexes. The HPLC analysis was performed using a Vydac C18 column,25 cm×4.6 mm column (5 μm pore size), equipped with a 2 cm guard column.Solvent A was 0.05 M triethylammonium phosphate buffer pH 2.5 andsolvent B was methanol. The method employed a gradient run over 30minutes at a flow rate of 1 ml/minute. The gradient ramped from 5-100% Bfrom 3-20 minutes.

To further explore this labeling method, Na₂CO₃ (0.004 g, 0.038 mmol),NaBH₄ (0.005 g, 0.13 mmol), and 2 mg of the DPMA derivative were placedin a vial. Next, the vial was sealed and flushed with CO for 10 min. Tothe vial was added 1 mL of Na ^(99m)TcO₄ ⁻ in saline. Finally thesolution was heated to 100° C. for 30 minutes. After cooling, thereaction was then checked for purity via HPLC by a Vydac C18 (5 mm, 25cm) column using methanol to elute the reaction products.

Alternatively, a ‘two pot’ synthesis could be performed, where the DPMAderivative was added after the formation of [^(99m)Tc(OH₂)₃(CO)₃]⁺.After cooling, 0.3 mL of 1 M PBS solution was added (pH 7.4), resultingin the stable formation of [^(99m)Tc(OH₂)₃(CO)₃]⁺. This Tc(I)tricarbonyl species was then heated at 75° C. for 30 minutes with theDPMA derivative to form the ^(99m)Tc-DPMA complex. The reaction was thenchecked for purity via HPLC by a Vydac C18 (5 mm, 25 cm) column usingmethanol to elute the reaction products. The versatility of the reactionallows for the reaction of a variety of sensitive biological DPMAderivatized ligands to be kept under idealized conditions.

Example 22 Synthesis of[Re(CO)₃(N-{ethyl-2-methoxy}-2-methyl-imidazole-3,4,5-trimethoxy-benzylamine)]

The [NEt₄]₂[Re(CO)₃(H₂O)₃] (0.06 g, 0.078 mmol) and[N-{ethyl-2-dimethoxy}-2-methyl-imidazole-3,4,5-trimethoxy-benzylamine](0.05 g, 0.094 mmol) were placed in a 100 ml pressure tube with a stirbar. The solids were dissolved in 2 ml of methanol. The solution washeated at 120° C. for 4 hrs. The solution was vacuumed down to residue.The residue was passed through a silca gel column using 10%methanol/methylene chloride as the solvents. The product eluted as therhenium complex (11.3 mg, 91.5%). ¹H NMR (CDCl₃), 300 MHz): 3.35 (s,6H), 3.46 (s, 6H), 3.87 (s, 3H), 3.94 (m, 2H), 3.96 (s, 6H), 4.40 (d,2H), 4.42 (m, 2H), 4.59 (s, 2H), 5.21 (dd, 2H), 5.86 (d, 2H), 6.72 (d,2H), 6.82 (s, 2H), 6.89 (d, 2H). LC/MS=M.W. 803. Calc. M.W.=803.

Example 23 Synthesis of[Re(CO)₃(N-{ethyl-2-diethoxy}-2-methyl-imidazole-3,4,5-trimethoxy-benzylamine)]

The [NEt₄]₂[Re(CO)₃(H₂O)₃] (0.014 g, 0.018 mmol) and[N-{ethyl-2-diethoxy}-2-methyl-imidazole-3,4,5-trimethoxy-benzylamine](0.013 g, 0.022 mmol) were placed in a 100 ml pressure tube with a stirbar. The solids were dissolved in 2 ml of methanol. The solution washeated at 110° C. for 4 hrs. The solution was vacuumed down to residue.The residue was passed through a silca gel column using 10%methanol/methylene chloride as the solvents. The product eluted as therhenium complex (16 mg, 44.6%). ¹H NMR (CDCl₃), 300 MHz): 1.21 (m, 12H),3.39 (m, 4H), 3.66 (m, 4H), 3.82 (d, 4H), 3.96 (s, 9H), 4.41 (d, 2H),4.58 (s, 4H), 5.11 (dd, 2H), 5.9 (d, 2H), 6.75 (d, 2H), 6.86 (s, 2H),6.90 (d, 2H). LC/MS=M.W. 860. Calc. M.W.=860.

Example 24 Synthesis of[Cu({N,N′-{N-ethyl-2-diethoxy}-2-methyl-imidazole}-N,N′-bis(2-hydroxybenzyl)-ethylenediamine})]

Placed CuCl₂ (0.004 g, 0.0027 mmol) in a 100 ml pressure tube equippedwith a stirrer. The solid was dissolved in 2 ml of methanol, followed byaddition of the amine (0.02 g, 0.03 mmol). The solution was heated at105° C. for 2 hours. The solution was then vacuumed down to residue. Theresidue was passed through a silca gel column using 0-10%methanol/methylene chloride as the solvents, yielding 0.005 g, 25.3%yield. ES/MS=726-728: expected 727.

Example 25 Synthesis of[Re(CO)₃(N-3,5-dimethoxybenzyl-dipyridine-2-methylamine)]

The [NEt₄]₂[Re(CO)₃(H₂O)₃] (0.015 g, 0.019 mmol) and2-di(picoline)amine-N-3,5-dimethoxybenzyl (KM08-121) (0.0068 g, 0.019mmol) were placed in a 100 ml pressure tube with a stirr bar. The solidswere dissolved in 5 ml of methanol. The solution was heated at 130° C.for 3 hrs. The solution was vacuumed down to residue. The residue waspassed through a silca gel column using 10% methanol/methylene chlorideas the solvents. The product eluted as the rhenium complex (11.3 mg,91.5%). ¹H NMR (CDCl₃), 300 MHz): 1.17 (s, H), 1.56 (s, 3H), 3.47 (d,H), 3.87 (s, 3H), 4.64 (m, 2H), 5.73 (d, 2H), 6.59 (t, H), 6.75 (d, H),7.16 (t, 2H), 7.31 (m, H), 7.80 (t, 2H), 7.95 (d, 2H), 8.62 (d, 2H).LC/MS=M.W. 620. Calc. M.W.=619.

Example 26 Synthesis of[Re(CO)₃(N-ethyl-ethoxy-dipyridine-2-methylamine)]

The [NEt₄]₂[Re(CO)₃(H₂O)₃] (0.04 g, 0.052 mmol) and2-di(picoline)amine-N-ethyl ethoxy (KM08-131) (0.014 g, 0.052 mmol) wereplaced in a 100 ml pressure tube with a stirr bar. The solids weredissolved in 5 ml of methanol. The solution was heated at 130° C. for 2hrs. The solution was vacuumed down to residue. The residue was passedthrough a silca gel column using 10% methanol/methylene chloride as thesolvents. The product eluted as the rhenium complex (8 mg, 28.6%). ¹HNMR (CDCl₃), 300 MHz): 1.25 (t, 3H), 3.72 (d, 2H), 3.97 (t, 2H), 4.05(t, 2H), 4.55 (d, 2H), 6.10 (d, 2H), 7.18 (t, 2H), 7.80 (t, 2H), 7.95(d, 2H), 8.62 (d, 2H). LC/MS=M.W. 542.3 Calc. M.W.=542.2.

Example 27 Synthesis of ReCl₃{(C₅H₄NCH₂)₂N(CH₂COOCH₂CH₃)}

To a solution of [ReOCl₃(PPh₃)₂] (0.0822 g, 0.0986 mmol) in 1 mL ofchloroform was added dropwise a solution of excess dipyridinemethylamineethyl acetate in 1 mL of chloroform. The solution remained olive greenuntil the addition of triethylamine (0.08 mL, 0.574 mmol) whereupon itimmediately changed from olive to forest green with precipation of theproduct. The solution was stirred for an additional 30 minutes and thenevaporated to dryness. X-ray quality crystals were grown by slowdiffusion of pentane into a solution of the compound in methylenechloride. ¹H NMR (CDCl₃, ppm): 1.25 (t, 3H), 3.45 (s, 2H), 3.95 (s, 4H),4.15 (q, 2H), 7.1 (m, 2H), 7.55 (m, 4H), 8.53 (s, 2H).

Example 28 Synthesis of ReCO₂{(C₅H₄NCH₂)₂NH₂)Br}

The use of [NEt₄]₂[ReBr₃(CO)₃], as the starting material leads to easyformation of the fac-Re(CO)₃(L)₃ core. The [NEt₄]₂[ReBr₃(CO)₃] wasreadily derived from the [ReBr(CO)₅]. The synthesis of the Re(I)complexes was accomplished by reacting [NEt₄]₂[ReBr₃(CO)₃] with theappropriate pyridine-2-methylamine in the ratio of 1:2 in 10 mL of H₂O.The reaction was allowed to heat at 80° C. for 3 hours. After coolingthe reaction products were purified using a small silica column using95% methylene chloride 5% methanol. X-ray quality crystals were grown byslow diffusion of pentane into a solution of the compound in methylenechloride.

Example 29 Synthesis of [Re(CO)₃{(2-C₅H₄NCH₂)₂}N—CH₃]

The synthesis of the Re(I) complexes was accomplished by reacting[NEt₄]₂[ReBr₃(CO)₃] with the appropriate pyridine-2-methylamine in theratio of 1:2 in 10 mL of H₂O. The reaction mixture was heated at 80° C.for 3 hours. After cooling, the reaction products were purified using asmall silica column using methylene chloride (95%)/methanol (5%) aseluent. ESMS m/z=484 (observed).

Example 30 Synthesis of [{N,N-di(pyridyl-2-methyl)}N-butyl-phthalimide]and Tc-99m Labeling Thereof

The dipyridinemethylamine (0.5 g, 2.51 mmol) andN-(4-bromobutyl)-phthalimide (0.85 g, 3.02 mmol) were mixed in a 100 mLpressure tube in 2 mL of DMF. Potassium carbonate (0.05 g) was added tothe solution. The mixture was heated at 120 C. for 1 hr. The reactionmixture was vacuumed down to residue. The residue was purified through apad of silica gel using methanol-methylene chloride to provide theproduct in 41% yield. ¹H NMR(CDCl₃): 1.57 (m), 2.54 (m), 2.85 (s), 2.93(s), 3.58 (m), 3.76 (s), 7.09 (m), 7.52 (d), 7.61 (m), 7.68 (m), 7.80(m), 7.99 (d), 8.44 (d).

[^(99m)Tc(CO)₃(H₂O)₃]⁺ was heated with[{N,N-di(pyridyl-2-methyl)}N-butyl-phthalimide in 0.5 mL (1 mg/mL) ofmethanol at 100° C. for 60 minutes. Purity, analyzed via C18 HPLC,showed >99% RCY. The product eluted with methanol at 20.8 minutes. TheHPLC analysis was performed using a Supelco C18 column, 25 cm×4.6 mmcolumn (5 μm pore size), equipped with 2 cm guard using solvent A=0.05 Mtriethylammonium phosphate buffer pH 2.5 and solvent B=methanol. Themethod employed was a gradient 5-95% B, 1 mL/minute for 30 minutes. Thegradient ramped from 5-95 from 3-20 minutes. In challenge experimentsthe HPLC purified product demonstrated no degradation in either 10 mMCysteine or Histidine in PBS pH 7.2 at 37° C. for 20 hrs.

Example 31 1. Synthesis

(a) Preparation of [ε-{N,N-di(pyridyl-2-methylene)}-L-lysine]

In a 100 ml roundbottom flask was placed[ε-{N,N—(C₅H₄N-2-CH₂)₂}-α-(fmoc)-L-lysine] (0.20 g, 0.36 mmoles) and anequal molar amount of 4-dimethylaminopyridine. The solids were dissolvedin 5 ml of DMF and 1 ml of methanol. The reaction mixture was allowed tostir at room temperature for 12 hrs. Finally, the reactions werepurified using large silica columns (20% methanol/methylene chloride).¹H NMR (CDCl₃): 1.30 (m, 2H), 2.25 (m, 2H), 3.04 (m, 2H), 3.14 (s, 9H),3.20 (m, 2H), 4.31 (s, 2H), 7.72 (t, 2H), 7.80 (d, 2H), 8.24 (t, 2H),8.64 (d, 2H).

(b) Preparation of [ε-{N,N-di(thiazole-2-methylene)}-L-lysine]

In a 100 ml roundbottom flask was placed[ε-{N,N—(C₃H₂NS-2-CH₂)₂}-α-(fmoc)-L-lysine] (0.050 g, 0.089 mmoles) andan equal molar amount of 4-dimethylaminopyridine. The solids weredissolved in 5 ml of DMF and 1 ml of methanol. The reaction mixture wasallowed to stir at room temperature for 12 hrs. Finally, the reactionswere purified using large silica columns (0-40% methanol/methylenechloride). ¹H NMR (D₂O): 1.35 (m, 2H), 1.61 (m, 2H), 1.81 (m, 2H), 2.63(t, 2H), 3.69 (t, H), 4.09 (s, 4H), 7.57 (d, 2H), 7.73 (d, 2H).

(c) Preparation of [ε-{N-(pyridyl-2-methylene)N-(acetic acid)}-L-lysine]

In a 100 ml roundbottom flask was placed[ε-{N—(C₅H₄N-2-CH₂)—N—(CH₂COOH)}-α-(fmoc)-L-lysine] (0.070 g, 0.177mmoles) and 4 ml of triflouroacetic acid. The reaction mixture wasallowed to stir at room temperature for 1.5 hrs. The solution was blowndry using nitrogen. Finally, the reactions were purified using largesilica columns (0-40% methanol/methylene chloride). ¹H NMR(CDCl₃): ¹HNMR (d6-DMSO): 1.39 (m, 2H), 1.62 (m, 2H), 1.75 (m, 2H), 3.01 (m, 2H),3.87 (m, 2H), 4.40 (d, 2H), 7.47 (m, H), 7.56 (d, H), 7.92 (m, H), 8.15(s, 2H), 8.62 (d, H), 9.17 (s, H).

Example 32 Synthesis of Copper Complexes of Fmoc-DpK[CuCl{η³-ε-[(N,N-di(pyridyl-2-methyl)]α(fmoc) lysine}]

To a solution of CuCl₂ in 10 mL of methanol was added an excess of Fmocprotected dipyridine lysine (Fmoc-DpK). The solution was heated at 150C. for 3 hours in a 100 ml sealed pressure tube. Upon completion thesolution was cooled and vacuumed down to residue. The residue wasdissolved in methylene chloride and layered with ether. After 12 hours adark green-blue oil formed. The oil was sent out for ES/MS resulting inan observed masses of 648-650, which corresponds to the [CuCl(DpK)]complex. The oily product was cleaned up using a Waters C18 sep pakusing 10% ethanol/H₂O for the load. The purified product weighed 60 mgfor 81% yield. ¹H NMR (CDCl₃, 300 mhz, ppm) was performed: 1.23(m), 3.71(d), 3.83 (m), 4.19 (m), 4.35 (s), 7.13 (m), 7.26 (m), 7.35 (m), 7.46(m), 7.51 (m), 7.61 (m), 7.72 (m), 8.51 (s). HPLC analysis was performedon a Vydac C18 column, 25 cm×4.6 mm column (5 μm pore size), equippedwith 2 cm guard using solvent A=H2O+0.1% TFA B=CH3CN+0.1% TFA. Themethod employed was a gradient 15-80% B, 1 mL/minute for 30 minutes. Thegradient ramped from 15-80 from 3-22 minutes. The product eluted as twopeaks (racemic mix of DpK ligand) at 19.3 and 19.6 minutes.

[⁶⁴CuCl{η³-ε-[(N,N-di(pyridyl-2-methyl)]α(fmoc) lysine}]

⁶⁴CuCl₂ was heated with Fmoc protected dipyridine lysine (Fmoc-DpK) in0.5 mL (100 μg/mL) of methanol at 70° C. for 20 minutes. Purity,analyzed via C18 HPLC, showed >85% RCY. The product eluted at 19.8minutes.

Example 33 Animal Studies (Prophetic)

Vertebrate animals are used to investigate the biodistribution andpharmacokinetics of the radionuclide-bound quinoline and isoquinolinederivatives and determine their uptake in the heart. Rats (SpragueDawley, male, at 80-100 grams each) are used for the whole bodybiodistribution studies. The Tc-complexes, as well as Cardiolite™, areevaluated at three time points; 5, 30, and 120 minutes, with fiveanimals per time point. In order to provide accurate statistics in theclearance rate measurements and to account for intra-species variationit is necessary to use this number of animals. The product is diluted to˜10 μCi/100 μl using freshly prepared 10% ethanol/saline (0.9%)solution. The rats are injected via a lateral tail vein with a volume of0.1 mL. The rats are then sacrificed by decapitation, with immediateblood collection at the desired time points. Whole body biodistributionsare performed on the animals immediately following decapitation, organand tissue samples are taken and washed of excess blood, blotted dry andweighed. Radioactivity is assayed using automated NaI well counter. Alltissue samples are counted together along with an aliquot of theinjected dose so that % injected dose and % injected dose per gram oftissue could be calculated.

See Boschi, A. et al. Synthesis and Biological Evaluation ofMonocationic Asymmetric 99mTc-Nitride Heterocomplexes Showing High HeartUptake and Improved Imaging Properties. J. Nucl. Med. (2003) 44:806-814.

Example 34 Biodistribution of Tc-99m-Heteroaryl Compounds of theInvention (Prophetic)

The biodistribution of Tc-99m bound compounds of the instant inventionare investigated in male rats (Sprague Dawley, n=5/timepoint, ˜180 gms).The compounds are injected via the tail vein in saline (e.g. 10 μCi/100μl). Animals are sacrificed at 5, 30, 60 and 120 minutes p.i. anddistribution is measured, for example, in the blood, heart, lung, liver,kidney, and GI track. Results shown in FIG. 4.

Example 35 Heart Imaging Agents (Prophetic)

Vertebrate animals (e.g., rats) are used to investigate thebiodistribution and pharmacokinetics of the new technetium complexes anduptake in the heart is determined. Rats (Sprague Dawley, male, at 80-100grams each) are used for whole body biodistribution studies. Thecompounds are evaluated at two time points, i.e., 5 and 60 minutes, withfour animals per time point. The use of this number of animals providesaccurate statistics in the clearance rate measurements, and accounts forintraspecies variation.

Example 36 1. Ethyl[(2-Pyridylmethyl)-2-(1-methylimidazolylmethyl)]aminoacetate (L¹⁰Et)

To a solution of 1-methylimidazole-2-aldehyde (5 g, 45.1 mmol) in 80 mLof methanol was added slowly a solution of 2-picolylamine (4.88 g, 45.1mmol) in 20 mL of methanol, and the solution was stirred for 2 h. Atthis time, the reactants were completely consumed. To this reactionmixture was added NaBH₄ (1.7 g, 45.1 mmol) in portions, and the solutionwas stirred for another 3 h, whereupon the solution was evaporated todryness and the residue was extracted with chloroform and concentrated.This residue was dissolved in anhydrous dimethylformamide (40 mL).Potassium carbonate (7.53 g, 45.1 mmol) and ethyl bromoacetate (6.23 g,45.1 mmol) were added to the solution under an argon atmosphere. Theresulting suspension was protected from light and allowed to stir at 30°C., under argon, for 32 h. The reaction mixture was filtered, and thefiltrate was evaporated to dryness. The resulting red oil was purifiedby silica gel column chromatography using a MeOH/CHCl₃ (5:95) solutionto give 7.80 g of the product. Yield: 60%. ¹H NMR (δ(ppm), MeOH-d4):8.33 (d, J) 4.2 Hz, 1H, PyH), 7.67 (t, J) 7.5 Hz, 1H, PyH), 7.36 (d, J)8.1 Hz, 1H, PyH), 7.18 (t, J) 6.9 Hz, 1H, PyH), 6.89 (d, J) 1.2 Hz, 1H,ImH), 6.71 (d, J) 1.2 Hz, 1H, ImH), 3.86 (s, 2H, PyCH₂), 3.83 (s, 2H,ImCH₂), 3.58 (s, 3H, NCH₃), 3.22 (s, 2H, NCH₂), 3.99 (q, J) 14.4 Hz, 2H,OCH₂), 1.13 (t, J) 7.2 Hz, 3H, CH₃). ¹³C NMR (δ(ppm), MeOH-d4): 172.23(C, CO₂Et), 159.93 (C, Py), 149.72 (CH, Py), 146.26 (C, Im), 138.69 (CH,Py), 127.22 (CH, Py), 125.01 (CH, Py), 123.99 (CH, Im), 123.71 (CH, Im),60.66 (C, PyCH₂), 55.54 (C, ImCH₂), 51.39 (C, NCH₃), 33.56 (C, NCH₂),61.62 (C, OCH₂), 14.73 (C, CH₃).

2. [Re(CO)₃(L¹⁰Et)]Br

To a stirred solution of [NEt₄]2[Re(CO)₃Br₃] (0.358 g, 0.465 mmol) in 40mL of methanol was added L¹⁰Et (0.134 g, 0.465 mmol) in 4 mL ofmethanol, and the solution was refluxed for 5 h. After cooling to roomtemperature, the solution was filtered and evaporated to dryness. Theresidue was dissolved in dichloromethane and carefully layered withhexane to give colorless crystals suitable for X-ray crystallography.Yield: 82%. Anal. Calcd (found) for C₁₈H₂₀BrN₄O₅Re: C, 33.86 (33.79); H,3.16 (3.46); N, 8.77 (8.69). ¹H NMR (δ(ppm), MeOH-d4): 8.80 (d, J) 5.4Hz, 1H, PyH), 8.04 (t, J) 6.3 Hz, 1H, PyH), 7.72 (d, J) 7.8 Hz, 1H,PyH), 7.45 (t, J) 6.6 Hz, 1H, PyH), 7.14 (d, J) 1.8 Hz, 1H, InH), 7.11(d, J) 1.5 Hz, 1H, ImH), 5.43 (d, J) 16.2 Hz, 2H, PyCH₂), 4.85 (d, J)11.7 Hz, 2H, ImCH₂), 4.71 (d, J) 4.2 Hz, 2H, NCH₂), 4.33 (q, J) 14.4 Hz,2H, OCH₂), 3.60 (s, 3H, NCH₃), 1.36 (t, J) 7.2 Hz, 3H, CH₃). ¹³C NMR(δ(ppm), MeOH-d4): 196.91, 195.96 (fac-Re-CO₃), 170.05 (CO₂Et), 160.84(C, Py), 153.92 (C, Im), 153.34 (CH, Py), 141.72 (CH, Py), 128.75 (CH,Py), 127.17 (CH, Py), 125.66 (CH, Im), 125.43 (CH, Im), 70.69 (C,PyCH₂), 68.67 (C, ImCH₂), 63.17 (C, NCH₂), 59.15 (C, OCH₂), 34.89 (C,NCH₃), 14.51 (C, CH₃). IR (KBr, ν/cm⁻¹): 2022, 1922, 1906(ν(fac-Re(CO)₃)); 1746 (ν_(as)(C═O)), 1208 (ν_(sym),(C═O)) of the acidgroup.

3. Ethyl [Bis{2-(1-methylimidazolylmethyl)}amino]acetate (L¹¹Et)

The preparation of L¹¹Et is based on literature procedures (Oberhausen,K. J.; Richardson, J. F.; Buchanan, R. M.; Pierce, Q. Polyhedron 1989,8, 659; and Chen, S.; Richardson, J. F.; Buchanan, R. M. Inorg. Chem.1994, 33, 2376) with minor modifications.

(a) Preparation of Bis(2-(1-methylimidazolyl)methyl)amine (L¹¹)

A solution of methyl-2-imidazolcarboxaldehyde oxime (5 g, 40 mmol) inmethanol (120 mL) was hydrogenated at atmospheric pressure and roomtemperature with 10% palladium charcoal for 5 days. The catalyst wasfiltered through Celite, and the filtrate was evaporated to give a whitepowder as L¹¹. Yield: 78%. ¹H NMR (δ (ppm), MeOH-d4): 6.85 (d, J) 1.2Hz, 2H, ImH), 6.70 (d, J) 1.2 Hz, 2H, ImH), 3.67 (s, 4H, ImCH₂), 3.48(s, 6H, NCH₃). ¹³C NMR (δ (ppm), methanol-d4): 147.71 (2C, Im), 127.25(2CH, In), 123.31 (2CH, Im), 45.23 (2C, ImCH₂), 33.37 (2C, NCH₃).

(b) Preparation of L¹¹Et

Potassium carbonate (2.43 g, 17.56 mmol) and ethyl bromoacetate (1.76 g,10.54 mmol) were added to a solution ofbis(2-(1-methylimidazolyl)methyl)amine (L¹¹) (1.8 g, 8.78 mmol) indimethylformamide under an argon atmosphere. The resulting suspensionwas sheltered from light and allowed to stir at room temperature for 5days. Water was added to the resulting mixture, and the solution wasextracted with chloroform (3×50 mL). After the solvent was evaporated,the resulting oil was purified by silica gel column chromatography usinga MeOH/CHCl3 (5:95) solution to give L¹¹Et as white powder. Yield: 1.05g (41%). ¹H NMR (δ(ppm), MeOH-d4): 6.87 (d, J) 1.2 Hz, 2H, ImH), 6.79(d, J) 1.2 Hz, 2H, ImH), 4.06 (q, J) 14.4 Hz, 2H, OCH₂), 3.75 (s, 4H,ImCH₂), 3.51 (s, 6H, NCH₃), 3.35 (s, 2H, NCH₂CO₂), 1.19 (t, J) 7.2 Hz,3H, CH₃). ¹³C NMR (δ(ppm), MeOH-d4): 172.09 (C, CO₂Et), 146.24 (2C, Im),127.17 (2CH, Im), 123.79 (2CH, Im), 61.73 (C, OCH₂), 55.03 (2C, ImCH₂),52.37 (2C, NCH₃), 33.24 (C, NCH₂), 14.67 (C, CH₃).

4. [Re(CO)₃(L¹¹Et)]

The same procedure as for [Re(CO)₃(L¹⁰Et)] was employed. Yield: 66%.Anal. Calcd (found) for C₁₇H₂₁BrN₅O₅Re: C, 31.83 (31.99); H, 3.30(3.46); N, 10.92 (10.93). ¹H NMR (δ(ppm), MeOH-d4): 7.29 (d, J) 1.5 Hz,2H, ImH), 7.17 (d, J) 1.5 Hz, 2H, ImH), 5.29, 4.88 (dd, J) 16.5 Hz, 4H,ImCH₂), 4.79 (s, 2H, NCH₂), 4.44 (q, J) 14.4 Hz, 2H, OCH₂), 3.86 (s, 6H,NCH₃), 1.43 (t, J) 7.2 Hz, 3H, CH₃). ¹³C NMR (δ(ppm), methanol-d4):197.15, 195.90 (fac-Re(CO)₃), 169.97 (C, COOEt), 152.40 (2C, Im), 128.58(2CH, Im), 125.26 (2CH, Im), 68.77 (C, NCH₂), 63.12 (C, OCH₂), 61.18(2C, ImCH₂), 35.39 (2C, NCH₃), 14.56 (C, CH₃). IR (KBr, ν/cm⁻¹): 2022,1922, 1901 (ν(fac-Re(CO)₃)); 1743 (ν_(as)(C═O)), 1212 (ν_(sym)(C═O)) ofthe carboxylate group.

Example 37 Peptide Synthesis and Characterization (Prophetic)

Peptides are prepared on an Advanced ChemTech 348Ω Peptide Synthesizerusing HBTU as the coupling agent (Chan, W. C., White, P. D. FMOCSolid-Phase Peptide Synthesis, A Practical Approach. Oxford UniversityPress: New York, 2000; Fields, G. B., Noble, R. L. (1990) Solid-phasepeptide synthesis utilizing 9-fluorenylmethoxycarbonyl amino acids. Int.J. Peptide Protein. Res. 35, 161-214; and Fields, C. G., Lloyd, D. H.,Macdonald, R. L., Otteson, K. M., Noble, R. L. (1991) HBTU Activationfor automated Fmoc solid-phase peptide synthesis. Pept. Res. 4, 95-101).The Fmoc protected chelate or its organometallic complex, as the bromidesalt, are dissolved in DMF and coupled to the growing peptide chainusing about a 4-fold excess of ligand. The duration of the couplingsteps to afford complete conversion is determined by exposing samples ofresin taken from the reaction mixtures to a solution containingninhydrin. The time to complete conversion of the amine to the amide inboth cases is identical to the conditions used for natural amino acidderivatives. As a result, modification of standard peptide couplingprotocols is not necessary. Peptides are cleaved from the resin using aTFA solution containing ethanedithiol (EDT, 2%), water (2%), andtriisopropylsilane (TIS, 2%). Because of the presence of methionine,exclusion of oxygen and the use of freshly distilled EDT is necessary toavoid oxidation of the thioether to the sulfoxide. Precipitation of thepeptide TFA salts is brought about by trituration with cold ether. Theresulting solids are collected by centrifugation and washed with coldether. Following dissolution in distilled water and lyophilization,compounds are collected as solids.

INCORPORATION BY REFERENCE

All of the patents and publications cited herein are hereby incorporatedby reference.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described herein. Such equivalents areintended to be encompassed by the following claims.

We claim:
 1. A compound of formula F:

wherein, independently for each occurrence, L is

X is —N(R²)—, —O—, or —S—; R is halogen, alkenyl, alkynyl, hydroxyl,alkoxyl, acyl, acyloxy, acylamino, silyloxy, amino, nitro, sulfhydryl,alkylthio, imino, amido, phosphoryl, phosphonate, phosphine, carbonyl,carboxyl, carboxamide, anhydride, silyl, thioalkyl, alkylsulfonyl,arylsulfonyl, selenoalkyl, ketone, aldehyde, ester, heteroalkyl, cyano,guanidine, ami dine, acetal, ketal, amine oxide, aryl, heteroaryl,aralkyl, heteroaralkyl, azido, aziridine, carbamoyl, epoxide, hydroxamicacid, imide, oxime, sulfonamide, thioamide, thiocarbamate, urea,thiourea, or —(CH₂)_(d)—R₈₀; R₈₀ is carboxaldehyde, carboxylate,carboxamido, alkoxycarbonyl, aryloxycarbonyl, ammonium, aryl,heteroaryl, cycloalkyl, cycloalkenyl, heterocyclyl, polycyclyl, aminoacid, peptide, saccharide, ribonucleic acid, or (deoxy)ribonucleic acid;R₂ is H or a lipophilic group; d is an integer in the range 0 to 12inclusive; m is an integer in the range 0 to 6 inclusive; n is aninteger in the range 0 to 6 inclusive; and the compound is complexedwith a radionuclide.
 2. The compound of claim 1, wherein theradionuclide is technetium or rhenium.
 3. A compound of formula G:

wherein, independently for each occurrence, R is absent or present 1 or2 times; R is halogen, alkyl, alkenyl, alkynyl, hydroxyl, alkoxyl, acyl,acyloxy, acylamino, silyloxy, amino, nitro, sulfhydryl, alkylthio,imino, ami do, phosphoryl, phosphonate, phosphine, carbonyl, carboxyl,carboxamide, anhydride, silyl, thioalkyl, alkylsulfonyl, arylsulfonyl,selenoalkyl, ketone, aldehyde, ester, heteroalkyl, cyano, guanidine, amidine, acetal, ketal, amine oxide, aryl, heteroaryl, aralkyl,heteroaralkyl, azido, aziridine, carbamoyl, epoxide, hydroxamic acid,imide, oxime, sulfonamide, thioamide, thiocarbamate, urea, thiourea, or—(CH₂)_(d)—R₈₀; R₈₀ is carboxaldehyde, carboxylate, carboxamido,alkoxycarbonyl, aryloxycarbonyl, ammonium, aryl, heteroaryl, cycloalkyl,cycloalkenyl, heterocyclyl, polycyclyl, amino acid, peptide, saccharide,ribonucleic acid, or (deoxy)ribonucleic acid; R₂ is H or a lipophilicgroup; d is an integer in the range 0 to 12 inclusive; m is an integerin the range 0 to 6 inclusive; n is an integer in the range 0 to 6inclusive; and the compound is complexed with a radionuclide.
 4. Thecompound of claim 3, wherein the radionuclide is technetium or rhenium.5. The compound of claim 3, wherein m is
 1. 6. The compound of claim 3,wherein n is
 1. 7. The compound of claim 3, wherein m is 1; and n is 1.8. The compound of claim 3, wherein R is absent.
 9. The compound ofclaim 3, wherein R₂ is a lipophilic group.
 10. The compound of claim 3,wherein R₂ is an ether, aralkyl, or alkyl aryl.
 11. The compound ofclaim 3, wherein R is absent; and R₂ is an ether, aralkyl, or alkylaryl.
 12. The compound of claim 3, wherein m is 1; n is 1; R is absent;and R₂ is an ether, aralkyl, or alkyl aryl.
 13. The compound of claim 3,wherein m is 1; n is 1; R is absent; and R₂ is an ether, aralkyl, oralkylaryl.
 14. The compound of claim 3, wherein m is 1; n is 1; R isabsent; R₂ is an ether, aralkyl, or alkylaryl; and wherein saidradionuclide is technetium or rhenium.
 15. A compound of formula H:

wherein: independently for each occurrence, L is

X is —N(R²)— or —O—; R is halogen, alkenyl, alkynyl, hydroxyl, alkoxyl,acyl, acyloxy, acylamino, silyloxy, amino, nitro, sulfhydryl, alkylthio,imino, amido, phosphoryl, phosphonate, phosphine, carbonyl, carboxyl,carboxamide, anhydride, silyl, thioalkyl, alkylsulfonyl, arylsulfonyl,selenoalkyl, ketone, aldehyde, ester, heteroalkyl, cyano, guanidine,amidine, acetal, ketal, amine oxide, aryl, heteroaryl, aralkyl,heteroaralkyl, azido, aziridine, carbamoyl, epoxide, hydroxamic acid,imide, oxime, sulfonamide, thioamide, thiocarbamate, urea, thiourea, or—(CH₂)_(d)—R₈₀; R₈₀ is independently for each occurrence carboxaldehyde,carboxylate, carboxamido, alkoxycarbonyl, aryloxycarbonyl, ammonium,aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocyclyl, polycyclyl,amino acid, peptide, saccharide, ribonucleic acid, or (deoxy)ribonucleicacid; R₂ is H or a lipophilic group; R₃ is a moiety selected from thegroup consisting of a neutral or anionic Lewis base, H, alkyl,hydroxyalkyl, alkoxyalkyl, amino alkyl, thioalkyl, alkenyl, alkynyl,aryl, heteroaryl, aralkyl, heteroaralkyl, acyl, aminoacyl, hydroxyacyl,thioacyl, (amino)alkoxycarbonyl, (hydroxy)alkoxycarbonyl,(amino)alkylamino carbonyl, (hydroxy)alkylaminocarbonyl, —CO₂H,—(CH₂)_(d)—R₈₀, or an amino acid radical; d is an integer in the range 0to 12 inclusive; m is an integer in the range 0 to 6 inclusive; n is aninteger in the range 0 to 6 inclusive; and the compound is complexedwith a radionuclide.
 16. The compound of claim 15, wherein theradionuclide is technetium or rhenium.
 17. A compound of formula I:

wherein, independently for each occurrence, R is absent or present 1 or2 times; R is halogen, alkyl, alkenyl, alkynyl, hydroxyl, alkoxyl, acyl,acyloxy, acylamino, silyloxy, amino, nitro, sulfhydryl, alkylthio,imino, amido, phosphoryl, phosphonate, phosphine, carbonyl, carboxyl,carboxamide, anhydride, silyl, thioalkyl, alkylsulfonyl, arylsulfonyl,selenoalkyl, ketone, aldehyde, ester, heteroalkyl, cyano, guanidine, amidine, acetal, ketal, amine oxide, aryl, heteroaryl, aralkyl,heteroaralkyl, azido, aziridine, carbamoyl, epoxide, hydroxamic acid,imide, oxime, sulfonamide, thioamide, thiocarbamate, urea, thiourea, or—(CH₂)_(d)—R₈₀; R₈₀ is carboxaldehyde, carboxylate, carboxamido,alkoxycarbonyl, aryloxycarbonyl, ammonium, aryl, heteroaryl, cycloalkyl,cycloalkenyl, heterocyclyl, polycyclyl, amino acid, peptide, saccharide,ribonucleic acid, or (deoxy)ribonucleic acid; R₂ is H or a lipophilicgroup; R₃ is a moiety selected from the group consisting of a neutral oranionic Lewis base, H, alkyl, hydroxyalkyl, alkoxyalkyl, aminoalkyl,thioalkyl, alkenyl, alkynyl, aryl, heteroaryl, aralkyl, heteroaralkyl,acyl, amino acyl, hydroxyacyl, thioacyl, (amino)alkoxycarbonyl,(hydroxy)alkoxycarbonyl, (amino)alkylaminocarbonyl,(hydroxy)alkylaminocarbonyl, —CO₂H, —(CH₂)_(d)—R₈₀, or an amino acidradical; d is an integer in the range 0 to 12 inclusive; m is an integerin the range 0 to 6 inclusive; n is an integer in the range 0 to 6inclusive; and the compound is complexed with a radionuclide.
 18. Thecompound of claim 17, wherein the radionuclide is technetium or rhenium.19. The compound of claim 17, wherein m is
 1. 20. The compound of claim17, wherein n is
 1. 21. The compound of claim 17, wherein m is 1; and nis
 1. 22. The compound of claim 17, wherein R is absent.
 23. Thecompound of claim 17, wherein R₂ is a lipophilic group.
 24. The compoundof claim 17, wherein R₂ is an ether, aralkyl, or alkyl aryl.
 25. Thecompound of claim 17, wherein R₃ is a moiety comprising an anionic Lewisbase.
 26. The compound of claim 17, wherein R₃ is a carboxylate,thiolate, or phenolate.
 27. The compound of claim 17, wherein R isabsent; and R₂ is an ether, aralkyl, or alkyl aryl.
 28. The compound ofclaim 17, wherein R is absent; R₂ is an ether, aralkyl, or alkylaryl;and R₃ is a carboxylate, thiolate, or phenolate.
 29. The compound ofclaim 17, wherein m is 1; n is 1; R is absent; and R₂ is an ether,aralkyl, or alkyl aryl.
 30. The compound of claim 17, wherein m is 1; nis 1; R is absent; R₂ is an ether, aralkyl, or alkylaryl; and R₃ is acarboxylate, thiolate, or phenolate.
 31. The compound of claim 17,wherein m is 1; n is 1; R is absent; and R₂ is an ether, aralkyl, oralkylaryl.
 32. The compound of claim 17, wherein m is 1; n is 1; R isabsent; R₂ is an ether, aralkyl, or alkylaryl; and R₃ is a carboxylate,thiolate, or phenolate.
 33. The compound of claim 17, wherein m is 1; nis 1; R is absent; and R₂ is an ether, aralkyl, or alkylaryl; andwherein the radionuclide is technetium or rhenium.
 34. The compound ofclaim 17, wherein m is 1; n is 1; R is absent; R₂ is an ether, aralkyl,or alkylaryl; and R₃ is a carboxylate, thiolate, or phenolate; andwherein the radionuclide is technetium or rhenium.
 35. A formulation,comprising a compound according to any of claim 1, 3, 15, or 17; and apharmaceutically acceptable excipient.
 36. A method of imaging a regionin a patient, comprising the steps of: administering to a patient adiagnostically effective amount of a compound of claim 1, 2, 3, 4, 13,14, 15, 16, 17, 18, or 31-34; and obtaining an image of said region ofsaid patient.
 37. The method of claim 36, wherein said region of saidpatient is the head or thorax.
 38. A compound represented by thefollowing formula:


39. The compound of claim 38, wherein the compound is complexed with aradionuclide.
 40. The compound of claim 39, wherein the radionuclide istechnetium or rhenium.
 41. A formulation, comprising a compoundaccording to claim 38; and a pharmaceutically acceptable excipient. 42.A method of imaging a region in a patient, comprising the steps of:administering to a patient a diagnostically effective amount of acompound of claim 39 and obtaining an image of said region of saidpatient.
 43. A method of imaging a region in a patient, comprising thesteps of: administering to a patient a diagnostically effective amountof a compound of claim 40 and obtaining an image of said region of saidpatient.